Best posts made by ferdinand

Hi,

thanks for the kind words both from Maxon and the community. I am looking forward to my upcoming adventures with the SDK Team and Cinema community.

Cheers,
Ferdinand

Hello @holgerbiebrach,

please excuse the wait. So, this is possible in Python and quite easy to do. This new behavior is just the old dialog folding which has been reworked a little bit. I have provided a simple example at the end of the posting. There is one problem regarding title bars which is sort of an obstacle for plugin developers which want to distribute their plugins, it is explained in the example below.

I hope this helps and cheers,
Ferdinand

The result:

The code:

"""Example for a command plugin with a foldable dialog as provided with the
Asset Browser or Coordinate Manger in Cinema 4D R25.

The core of this is just the old GeDialog folding mechanic which has been
changed slightly with R25 as it will now also hide the title bar of a folded
dialog, i.e., the dialog will be hidden completely.

The structure shown here mimics relatively closely what the Coordinate Manger
does. There is however one caveat: Even our internal implementations do not
hide the title bar of a dialog when unfolded. Instead, this is done via 
layouts, i.e., by clicking onto the ≡ icon of the dialog and unchecking the
"Show Window Title" option and then saving such layout. If you would want
to provide a plugin which exactly mimics one of the folding managers, you
would have to either ask your users to take these steps or provide a layout.

Which is not ideal, but I currently do not see a sane way to hide the title
bar of a dialog. What you could do, is open the dialog as an async popup which 
would hide the title bar. But that would also remove the ability to dock the 
dialog. You could then invoke `GeDialog.AddGadegt(c4d.DIALOG_PIN, SOME_ID)`to 
manually add a pin back to your dialog, so that you can dock it. But that is 
not how it is done internally by us, as we simply rely on layouts for that.
"""

import c4d


class ExampleDialog (c4d.gui.GeDialog):
    """Example dialog that does nothing.

    The dialog itself has nothing to do with the implementation of the
    folding.
    """
    ID_GADGETS_START = 1000
    ID_GADGET_GROUP = 0
    ID_GADGET_LABEL = 1
    ID_GADGET_TEXT = 2

    GADGET_STRIDE = 10
    GADEGT_COUNT = 5

    def CreateLayout(self) -> bool:
        """Creates dummy gadgets.
        """
        self.SetTitle("ExampleDialog")
        flags = c4d.BFH_SCALEFIT

        for i in range(self.GADEGT_COUNT):
            gid = self.ID_GADGETS_START + i * self.GADGET_STRIDE
            name = f"Item {i}"

            self.GroupBegin(gid + self.ID_GADGET_GROUP, flags, cols=2)
            self.GroupBorderSpace(5, 5, 5, 5)
            self.GroupSpace(2, 2)
            self.AddStaticText(gid + self.ID_GADGET_LABEL, flags, name=name)
            self.AddEditText(gid + self.ID_GADGET_TEXT, flags)
            self.GroupEnd()
        return True


class FoldingManagerCommand (c4d.plugins.CommandData):
    """Provides the implementation for a command with a foldable dialog.
    """
    ID_PLUGIN = 1058525
    REF_DIALOG = None

    @property
    def Dialog(self) -> ExampleDialog:
        """Returns a class bound ExampleDialog instance.
        """
        if FoldingManagerCommand.REF_DIALOG is None:
            FoldingManagerCommand.REF_DIALOG = ExampleDialog()

        return FoldingManagerCommand.REF_DIALOG

    def Execute(self, doc: c4d.documents.BaseDocument) -> bool:
        """Folds or unfolds the dialog.

        The core of the folding logic as employed by the Asset Browser
        or the Coordinate manager in R25.
        """
        # Get the class bound dialog reference.
        dlg = self.Dialog
        # Fold the dialog, i.e., hide it if it is open and unfolded. In C++
        # you would also want to test for the dialog being visible with
        # GeDialog::IsVisible, but we cannot do that in Python.
        if dlg.IsOpen() and not dlg.GetFolding():
            dlg.SetFolding(True)
        # Open or unfold the dialog. The trick here is that calling
        # GeDialog::Open will also unfold the dialog.
        else:
            dlg.Open(c4d.DLG_TYPE_ASYNC, FoldingManagerCommand.ID_PLUGIN)

        return True

    def RestoreLayout(self, secret: any) -> bool:
        """Restores the dialog on layout changes.
        """
        return self.Dialog.Restore(FoldingManagerCommand.ID_PLUGIN, secret)

    def GetState(self, doc: c4d.documents.BaseDocument) -> int:
        """Sets the command icon state of the plugin.

        This is not required, but makes it a bit nicer, as it will indicate
        in the command icon when the dialog is folded and when not.
        """
        dlg = self.Dialog
        result = c4d.CMD_ENABLED
        if dlg.IsOpen() and not dlg.GetFolding():
            result |= c4d.CMD_VALUE

        return result


def RegisterFoldingManagerCommand() -> bool:
    """Registers the example.
    """
    return c4d.plugins.RegisterCommandPlugin(
        id=FoldingManagerCommand.ID_PLUGIN,
        str="FoldingManagerCommand",
        info=c4d.PLUGINFLAG_SMALLNODE,
        icon=None,
        help="FoldingManagerCommand",
        dat=FoldingManagerCommand())


if __name__ == '__main__':
    if not RegisterFoldingManagerCommand():
        raise RuntimeError(
            f"Failed to register {FoldingManagerCommand} plugin.")

Dear Community,

this question reached us via email-support in the context of C++, but I thought the answer might be interesting for other users too.

The underlying question in this case was how to project points from object or world space into the texture space of an object with UV data. I am showing here deliberately an approach that can be followed both in C++ and Python, so that all users can benefit from this. In C++ one has also the option of using VolumeData and its methods VolumeData::GetUvw or VolumeData::ProjectPoint but must then either implement a volume shader (as otherwise the volume data attached to the ChannelData passed to ShaderData::Output will be nullptr), or use VolumeData:: AttachVolumeDataFake to access ::ProjectPoint. There is however no inherent necessity to take this shader bound route as shown by the example.

Cheers,
Ferdinand

Result

The script has created a texture with red pixels for the intersection points of the rays cast from each vertex of the spline towards the origin of the polygon object. The script also created the null object rays to visualize the rays which have been cast.

raycast_texture.c4d : The scene file.

Code

You must save the script to disk before running it, as the script infers from the script location the place to save the generated texture to.

"""Demonstrates how to project points from world or object space to UV space.

This script assumes that the user has selected a polygon object and a spline object in the order
mentioned. The script projects the points of the spline object onto the polygon object and creates
a texture from the UV coordinates of the projected points. The texture is then applied to the
polygon object.

The script uses the `GeRayCollider` class to find the intersection of rays cast from the points of
the spline object to the polygon object. The UV coordinates of the intersection points are then
calculated using the `HairLibrary` class. In the C++ API, one should use maxon::
GeometryUtilsInterface::CalculatePolygonPointST() instead.

Finally, using GeRayCollider is only an example for projecting points onto the mesh. In practice,
any other method can be used as long as it provides points that lie in the plane(s) of a polygon.

The meat of the example is in the `main()` function. The other functions are just fluff.
"""

import os
import c4d
import mxutils
import uuid

from mxutils import CheckType

doc: c4d.documents.BaseDocument  # The currently active document.
op: c4d.BaseObject | None  # The primary selected object in `doc`. Can be `None`.

def CreateTexture(points: list[c4d.Vector], path: str, resolution: int = 1000) -> None:
    """Creates a texture from the given `points` and saves it to the given `path`.

    Parameters:
        path (str): The path to save the texture to.
        points (list[c4d.Vector]): The points to create the texture from.
    """
    # Check the input values for validity.
    if os.path.exists(path):
        raise FileExistsError(f"File already exists at path: {path}")
    if not path.endswith(".png"):
        raise ValueError("The path must end with '.png'.")

    # Create a drawing canvas to draw the points on.
    canvas: c4d.bitmaps.GeClipMap = CheckType(c4d.bitmaps.GeClipMap())
    if not canvas.Init(resolution, resolution, 24):
        raise MemoryError("Failed to initialize GeClipMap.")

    # Fill the canvas with white.
    canvas.BeginDraw()
    canvas.SetColor(255, 255, 255)
    canvas.FillRect(0, 0, resolution, resolution)

    # Draw the points on the canvas.
    canvas.SetColor(255, 0, 0)
    for p in points:
        x: int = int(p.x * resolution)
        y: int = int(p.y * resolution)
        x0: int = max(0, x - 1)
        y0: int = max(0, y - 1)
        x1: int = min(resolution, x + 1)
        y1: int = min(resolution, y + 1)
        canvas.FillRect(x0, y0, x1, y1)

    canvas.EndDraw()

    # Save the canvas to the given path.
    bitmap: c4d.bitmaps.BaseBitmap = CheckType(canvas.GetBitmap())
    bitmap.Save(path, c4d.FILTER_PNG)

    c4d.bitmaps.ShowBitmap(bitmap)

def ApplyTexture(obj: c4d.BaseObject, path: str) -> None:
    """Applies the texture at the given `path` to the given `obj`.
    """
    CheckType(obj, c4d.BaseObject)

    # Check the input values for validity.
    if not os.path.exists(path):
        raise FileNotFoundError(f"File does not exist at path: {path}")

    # Create a material and apply the texture to it.
    material: c4d.BaseMaterial = CheckType(c4d.BaseMaterial(c4d.Mmaterial), c4d.BaseMaterial)
    obj.GetDocument().InsertMaterial(material)

    shader: c4d.BaseShader = CheckType(c4d.BaseShader(c4d.Xbitmap), c4d.BaseShader)
    shader[c4d.BITMAPSHADER_FILENAME] = path
    material.InsertShader(shader)
    material[c4d.MATERIAL_COLOR_SHADER] = shader
    material[c4d.MATERIAL_PREVIEWSIZE] = c4d.MATERIAL_PREVIEWSIZE_1024

    # Apply the material to the object.
    tag: c4d.TextureTag = CheckType(obj.MakeTag(c4d.Ttexture))
    tag[c4d.TEXTURETAG_PROJECTION] = c4d.TEXTURETAG_PROJECTION_UVW
    tag[c4d.TEXTURETAG_MATERIAL] = material

def CreateDebugRays(spline: c4d.SplineObject, p: c4d.Vector) -> None:
    """Adds spline objects to the document to visualize the rays from the given `p` to the points of
    the given `spline`.
    """
    doc: c4d.documents.BaseDocument = CheckType(spline.GetDocument(), c4d.documents.BaseDocument)
    rays: c4d.BaseObject = c4d.BaseObject(c4d.Onull)
    rays.SetName("Rays")
    doc.InsertObject(rays)

    for q in spline.GetAllPoints():
        ray: c4d.SplineObject = c4d.SplineObject(2, c4d.SPLINETYPE_LINEAR)
        ray.SetPoint(0, p)
        ray.SetPoint(1, q * spline.GetMg())
        ray.Message(c4d.MSG_UPDATE)
        ray.InsertUnder(rays)

def main() -> None:
    """Carries out the main logic of the script.
    """
    # Check the object selection for being meaningful input.
    selected: list[c4d.BaseObject] = doc.GetActiveObjects(c4d.GETACTIVEOBJECTFLAGS_SELECTIONORDER)
    if (len(selected) != 2 or not selected[0].CheckType(c4d.Opolygon) or
        not selected[1].CheckType(c4d.Ospline)):
        raise ValueError("Please select a polygon object and a spline object.")

    polygonObject, splineObject = selected

    # Get the uvw tag, the points, and the polygons of the polygon object.
    uvwTag: c4d.UvwTag = mxutils.CheckType(polygonObject.GetTag(c4d.Tuvw))
    points: list[c4d.Vector] = [polygonObject.GetMg() * p for p in polygonObject.GetAllPoints()]
    polys: list[c4d.CPolygon] = polygonObject.GetAllPolygons()

    # We are casting here in a dumb manner towards the center of the polygon object. In practice,
    # one should cast rays towards the plane of the polygon object. Or even better, use another
    # method to project the points onto the polygon object, as GeRayCollider is not the most 
    # efficient thing in the world.
    rayTarget: c4d.Vector = polygonObject.GetMg().off
    CreateDebugRays(splineObject, rayTarget)

    # Initialize the GeRayCollider to find the intersection of rays cast from the points of the
    # spline object to the polygon object.
    collider: c4d.utils.GeRayCollider = c4d.utils.GeRayCollider()
    if not collider.Init(polygonObject):
        raise MemoryError("Failed to initialize GeRayCollider.")


    # Init our output list and iterate over the points of the spline object.
    uvPoints: list[c4d.Vector] = []
    for p in splineObject.GetAllPoints():

        # Transform the point from object to world space (q) and then to the polygon object's space
        # (ro). Our ray direction always points towards the center of the polygon object.
        q: c4d.Vector = splineObject.GetMg() * p
        ro: c4d.Vector = ~polygonObject.GetMg() * q
        rd: c4d.Vector = rayTarget - ro

        # Cast the ray and check if it intersects with the polygon object.
        if not collider.Intersect(ro, rd, 1E6) or collider.GetIntersectionCount() < 1:
            continue
        
        # Get the hit position and the polygon ID of the intersection.
        hit: dict = collider.GetNearestIntersection()
        pos: c4d.Vector = mxutils.CheckType(hit.get("hitpos", None), c4d.Vector)
        pid: int = mxutils.CheckType(hit.get("face_id", None), int)

        # One mistake would be now to use the barycentric coordinates that are in the intersection
        # data, as Cinema uses an optimized algorithm to interpolate in a quad and not the standard
        # cartesian-barycentric conversion. In Python these polygon weights are only exposed in a 
        # bit weird place, the hair library. In C++ these barycentric coordinates make sense because
        # there exist methods to convert them to weights. In Python the barycentric coordinates are
        # pretty much useless as we do not have such a conversion function here.

        # Compute the weights s, t for the intersection point in the polygon.
        s, t = c4d.modules.hair.HairLibrary().GetPolyPointST(
            pos, points[polys[pid].a], points[polys[pid].b],
                 points[polys[pid].c], points[polys[pid].d], True)

        # Get the uv polygon and bilinearly interpolate the coordinates using the weights. It would
        # be better to use the more low-level variable tag data access functions in VariableTag 
        # than UvwTag.GetSlow() in a real-world scenario.
        uvw: list[c4d.Vector] = list(uvwTag.GetSlow(pid).values())
        t0: c4d.Vector = c4d.utils.MixVec(uvw[0], uvw[1], s)
        t1: c4d.Vector = c4d.utils.MixVec(uvw[3], uvw[2], s)
        uv: c4d.Vector = c4d.utils.MixVec(t0, t1, t)

        # Append the UV coordinates to the output list.
        uvPoints.append(uv)

    # Write the UV coordinates to a texture and apply it to the polygon object.
    path: str = os.path.join(os.path.dirname(__file__), f"image-{uuid.uuid4()}.png")
    CreateTexture(uvPoints, path, resolution=1024)
    ApplyTexture(polygonObject, path)

    c4d.EventAdd()


if __name__ == '__main__':
    main()

Hi,

that your script is not working has not anything to do with pseudo decimals, but the fact that you are treating numbers as strings (which is generally a bad idea) in a not very careful manner. When you truncate the string representation of a number which is represented in scientific notation (with an exponent), then you also truncate that exponent and therefor change the value of the number.

To truncate a float you can either take the floor of my_float * 10 ** digits and then divide by 10 ** digits again or use the keyword round.

data = [0.03659665587738824,
        0.00018878623163019122,
        1.1076812650509394e-03,
        1.3882258325566638e-06]

for n in data:
    rounded = round(n, 4)
    floored = int(n * 10000) / 10000
    print(n, rounded, floored)

0.03659665587738824 0.0366 0.0365
0.00018878623163019122 0.0002 0.0001
0.0011076812650509394 0.0011 0.0011
1.3882258325566637e-06 0.0 0.0
[Finished in 0.1s]

Cheers
zipit

Dear community,

We will have to touch multiple parts of developers.maxon.net on the 18.01.2024 and 19.01.2024 22.01.2024. This will result in outages of our documentation and the forum these days. I will try to keep the outage times to a minimum and it will certainly not span the whole two days. But especially one task I will do on Friday might take hours to complete and I can only do that on a forum which is in maintenance mode.

Please make sure to download a recent offline documentation in case you plan to do extended development work the next two days. As a result, forum support might also be delayed on these days.

Cheers,
Ferdinand

Hi,

as @Cairyn said the problem is unreachable code. I also just saw now that you did assign the same ID to all your buttons in your CreateLayout(). Ressource and dialog element IDs should be unique. I would generally recommend to define your dialogs using a resource, but here is an example on how to do it in code.

BUTTON_BASE_ID = 1000
BUTTON_NAMES = ["Button1", "Button2", "Button3", "Button4", "Button5"]
BUTTON_DATA = {BUTTON_BASE_ID + i: name for i, name in enumerate(BUTTON_NAMES)}

class MyDialog(gui.GeDialog):

    def CreateLayout(self):
        """
        """
        self.GroupBegin(id=1013, flags=c4d.BFH_SCALEFIT, cols=5, rows=4)
        for element_id, element_name in BUTTON_DATA.items():
            self.AddButton(element_id, c4d.BFV_MASK, initw=100, 
                           name=element_name)
        self.GroupEnd()
        return True

    def Command(self, id, msg):
        """
        """
        if id == BUTTON_BASE_ID:
            print "First button has been clicked"
        elif id == BUTTON_BASE_ID + 1:
            print "Second button has been clicked"
        # ...
        if id in BUTTON_DATA.keys(): # or just if id in BUTTON_DATA
            self.Close()
        return True

Dear development community,

On September the 10th, 2024, Maxon Computer released Cinema 4D 2025.0.0. For an overview of the new features of Cinema 4D 2025.0, please refer to the release announcement. Alongside this release, a new Cinema 4D SDK and SDK documentation have been released, reflecting the API changes for 2025.0.0. The major changes are:

C++ API

• What was formerly has been know as the Classic API has been deprecated in favour of the Cinema API. Alongside this a new cinema namespace has been introduced which contains all the entities which were formerly in the anonymous global namespace known as the Classic API. Plugin authors must adopt their code to this new API, although the changes are not nearly as extensive as for 2024. See the 2025 migration guide for details. Code examples and documentation have been updated to now refer to a Cinema API.
• 2025 uses OCIO as the default color management mode, brings an improved color picker, and made general improvements to the consistency of the OCIO implementation. This had some effects on the underlying OCIO API which are reflected in two new code examples in the OCIO Manual and a new plugin in the SDK.

Python API

• Python also received the update from Classic to Cinema API. But here the change was more of a cosmetic nature confined to the documentation. The c4d package remains the home for all formerly Classic and now Cinema API entities.
• The mxutils package received updates around standardized scene traversal, random number generation, and more.
• Graph descriptions now support variadic ports of arbitrary complexity and explicit port references.

Head to our download section for the newest SDK downloads, or the C++ and Python API change notes for an in detail overview of the changes.

We discovered late in the cycle bugs in the Asset API code examples and OCIO code in the Python SDK. Which is why the publication of the Python SDK and GitHub code examples has been postponed until these bugs are fixed. They should be ready latest by Friday the 13th of September. But the Python online documentation is accessible and error free (to our knowledge).

We had to make some last minute changes to the C++ SDK regarding OCIO code examples. Only the extended C++ SDK contains these changes. The application provided sdk.zip will catch up with the next release of Cinema 4D.

Happy rendering and coding,
the Maxon SDK Team

Cloudflare unfortunately still does interfere with our server cache. And you might have to refresh your cache manually.

When you are not automatically redirected to the new versions, and also do not see 2024.5 in the version selector, please press CTRL + F5 or press CTRL and click on the reload icon of your browser anywhere on developers.maxon.net/docs/ to refresh your cache. You only have to do this once and it will apply to all documentations at once. Otherwise your cache will automatically update latest by 19/07/2024 00:00.

Hi,

sorry for all the confusion. You have to pass actual instances of objects. The following code does what you want (and this time I actually tried it myself ;)).

import c4d

def main():
    """
    """
    bc = doc.GetAllTextures(ar=doc.GetMaterials())
    for cid, value in bc:
        print cid, value

if __name__=='__main__':
   main()

Cheers,
zipit

Hi,

you use GetActiveDocument() in a NodeData environment. You cannot do this, since nodes are also executed when their document is not the active document (while rendering for example - documents get cloned for rendering).

Cheers
zipit

Hi,

you have to invoke AddUserArea and then attach an instance of your implemented type to it. Something like this:

my_user_area = MyUserAreaType()
self.AddUserArea(1000,*other_arguments)
self.AttachUserArea(my_user_area, 1000)

I have attached an example which does some things you are trying to do (rows of things, highlighting stuff, etc.). The gadget is meant to display a list of boolean values and the code is over five years old. I had a rather funny idea of what good Python should look like then and my attempts of documentation were also rather questionable. I just wrapped the gadget into a quick example dialog you could run as a script. I did not maintain the code, so there might be newer and better ways to do things now.

Also a warning: GUI stuff is usually a lot of work and very little reward IMHO.

Cheers
zipit

import c4d
import math
import random

from c4d import gui

# Pattern Gadget
IDC_SELECTLOOP_CELLSIZE = [32, 32]
IDC_SELECTLOOP_GADGET_MINW = 400
IDC_SELECTLOOP_GADGET_MINH = 32

class ExampleDialog(gui.GeDialog):
    """
    """
    def CreateLayout(self):
        """
        """

        self.Pattern = c4d.BaseContainer()
        for i in range(10):
            self.Pattern[i] = random.choice([True, False])
        self.PatternSize = len(self.Pattern)

        self.gadget = Patterngadget(host=self)
        self.AddUserArea(1000, c4d.BFH_FIT, 400, 32)
        self.AttachUserArea(self.gadget, 1000)
        return True

class Patterngadget(gui.GeUserArea):
    """
    A gui gadget to modify and display boolean patterns.
    """

    def __init__(self, host):
        """
        :param host: The hosting BaseToolData instance
        """
        self.Host = host
        self.BorderWidth = None
        self.CellPerColumn = None
        self.CellWidht = IDC_SELECTLOOP_CELLSIZE[0]
        self.CellHeight = IDC_SELECTLOOP_CELLSIZE[1]
        self.Columns = None
        self.Height = None
        self.Width = None
        self.MinHeight = IDC_SELECTLOOP_GADGET_MINH
        self.MinWidht = IDC_SELECTLOOP_GADGET_MINW
        self.MouseX = None
        self.MouseY = None

    """------------------------------------------------------------------------
        Overridden methods
        --------------------------------------------------------------------"""

    def Init(self):
        """
        Init the gadget.
        :return : Bool
        """
        self._get_colors()
        return True

    def GetMinSize(self):
        """
        Resize the gadget
        :return : int, int
        """
        return int(self.MinWidht), int(self.MinHeight)

    def Sized(self, w, h):
        """
        Get the gadgets height and width
        """
        self.Height, self.Width = int(h), int(w)
        self._fit_gadget()

    def Message(self, msg, result):
        """
        Fetch and store mouse over events
        :return : bool
        """
        if msg.GetId() == c4d.BFM_GETCURSORINFO:
            base = self.Local2Screen()
            if base:
                self.MouseX = msg.GetLong(c4d.BFM_DRAG_SCREENX) - base['x']
                self.MouseY = msg.GetLong(c4d.BFM_DRAG_SCREENY) - base['y']
                self.Redraw()
                self.SetTimer(1000)
        return gui.GeUserArea.Message(self, msg, result)

    def InputEvent(self, msg):
        """
        Fetch and store mouse clicks
        :return : bool
        """
        if not isinstance(msg, c4d.BaseContainer):
            return True
        if msg.GetLong(c4d.BFM_INPUT_DEVICE) == c4d.BFM_INPUT_MOUSE:
            if msg.GetLong(c4d.BFM_INPUT_CHANNEL) == c4d.BFM_INPUT_MOUSELEFT:
                base = self.Local2Global()
                if base:
                    x = msg.GetLong(c4d.BFM_INPUT_X) - base['x']
                    y = msg.GetLong(c4d.BFM_INPUT_Y) - base['y']
                    pid = self._get_id(x, y)
                    if pid <= self.Host.PatternSize:
                        self.Host.Pattern[pid] = not self.Host.Pattern[pid]
                        self.Redraw()
        return True

    def Timer(self, msg):
        """
        Timer loop to catch OnMouseExit
        """
        base = self.Local2Global()
        bc = c4d.BaseContainer()
        res = gui.GetInputState(c4d.BFM_INPUT_MOUSE,
                                c4d.BFM_INPUT_MOUSELEFT, bc)
        mx = bc.GetLong(c4d.BFM_INPUT_X) - base['x']
        my = bc.GetLong(c4d.BFM_INPUT_Y) - base['y']
        if res:
            if not (mx >= 0 and mx <= self.Width and
                    my >= 0 and my <= self.Height):
                self.SetTimer(0)
                self.Redraw()

    def DrawMsg(self, x1, y1, x2, y2, msg):
        """
        Draws the gadget
        """
        # double buffering
        self.OffScreenOn(x1, y1, x2, y2)
        # background & border
        self.DrawSetPen(self.ColBackground)
        self.DrawRectangle(x1, y1, x2, y2)
        if self.BorderWidth:
            self.DrawBorder(c4d.BORDER_THIN_IN, x1, y1,
                            self.BorderWidth + 2, y2 - 1)
        # draw pattern
        for pid, state in self.Host.Pattern:
            x, y = self._get_rect(pid)
            self._draw_cell(x, y, state, self._is_focus(x, y))

    """------------------------------------------------------------------------
        Public methods
        --------------------------------------------------------------------"""

    def Update(self, cid=None):
        """
        Update the gadget.
        :param cid: A pattern id to toggle.
        """
        if cid and cid < self.Host.PatternSize:
            self.Host.Pattern[cid] = not self.Host.Pattern[cid]
        self._fit_gadget()
        self.Redraw()

    """------------------------------------------------------------------------
        Private methods
        --------------------------------------------------------------------"""

    def _get_colors(self, force=False):
        """
        Set the drawing colors.
        :return : Bool
        """
        self.ColScale = 1.0 / 255.0
        if self.IsEnabled() or force:
            self.ColBackground = self._get_color_vector(c4d.COLOR_BG)
            self.ColCellActive = c4d.GetViewColor(
                c4d.VIEWCOLOR_ACTIVEPOINT) * 0.9
            self.ColCellFocus = self._get_color_vector(c4d.COLOR_BGFOCUS)
            self.ColCellInactive = self._get_color_vector(c4d.COLOR_BGEDIT)
            self.ColEdgeDark = self._get_color_vector(c4d.COLOR_EDGEDK)
            self.ColEdgeLight = self._get_color_vector(c4d.COLOR_EDGELT)
        else:
            self.ColBackground = self._get_color_vector(c4d.COLOR_BG)
            self.ColCellActive = self._get_color_vector(c4d.COLOR_BG)
            self.ColCellFocus = self._get_color_vector(c4d.COLOR_BG)
            self.ColCellInactive = self._get_color_vector(c4d.COLOR_BG)
            self.ColEdgeDark = self._get_color_vector(c4d.COLOR_EDGEDK)
            self.ColEdgeLight = self._get_color_vector(c4d.COLOR_EDGELT)
        return True

    def _get_cell_pen(self, state, _is_focus):
        """
        Get the color for cell depending on its state.
        :param state   : The state
        :param _is_focus : If the cell is hoovered.
        :return        : c4d.Vector()
        """
        if state:
            pen = self.ColCellActive
        else:
            pen = self.ColCellInactive
        if self.IsEnabled() and _is_focus:
            return (pen + c4d.Vector(2)) * 1/3
        else:
            return pen

    def _draw_cell(self, x, y, state, _is_focus):
        """
        Draws a gadget cell.
        :param x:       local x
        :param y:       local y
        :param state:   On/Off
        :param _is_focus: MouseOver state
        """
        # left and top bright border
        self.DrawSetPen(self.ColEdgeLight)
        self.DrawLine(x, y, x + self.CellWidht, y)
        self.DrawLine(x, y, x, y + self.CellHeight)
        # bottom and right dark border
        self.DrawSetPen(self.ColEdgeDark)
        self.DrawLine(x, y + self.CellHeight - 1, x +
                      self.CellWidht - 1, y + self.CellHeight - 1)
        self.DrawLine(x + self.CellWidht - 1, y, x +
                      self.CellWidht - 1, y + self.CellHeight - 1)
        # cell content
        self.DrawSetPen(self._get_cell_pen(state, _is_focus))
        self.DrawRectangle(x + 1, y + 1, x + self.CellWidht -
                           2, y + self.CellHeight - 2)

    def _get_rect(self, pid, offset=1):
        """
        Get the drawing rect for an array id.
        :param pid    : the pattern id
        :param offset : the pixel border offset
        :return       : int, int
        """
        pid = int(pid)
        col = pid / self.CellPerColumn
        head = pid % self.CellPerColumn
        return self.CellWidht * head + offset, self.CellHeight * col + offset

    def _get_id(self, x, y):
        """
        Get the array id for a coord within the gadget.
        :param x : local x
        :param y : local y
        :return  : int
        """
        col = (y - 1) / self.CellHeight
        head = (x - 1) / self.CellWidht
        return col * self.CellPerColumn + head

    def _is_focus(self, x, y):
        """
        Test if the cell coords are under the cursor.
        :param x : local x
        :param y : local y
        :return  : bool
        """
        if (self.MouseX >= x and self.MouseX <= x + self.CellWidht and
                self.MouseY >= y and self.MouseY <= y + self.CellHeight):
            self.MouseX = c4d.NOTOK
            self.MouseY = c4d.NOTOK
            return True
        else:
            return False

    def _fit_gadget(self):
        """
        Fit the gadget size to the the array
        """
        oldHeight = self.MinHeight
        self.CellPerColumn = int((self.Width - 2) / self.CellWidht)
        self.Columns = math.ceil(
            self.Host.PatternSize / self.CellPerColumn) + 1
        self.MinHeight = int(IDC_SELECTLOOP_GADGET_MINH * self.Columns) + 3
        self.MinWidht = int(IDC_SELECTLOOP_GADGET_MINW)
        self.BorderWidth = self.CellWidht * self.CellPerColumn
        if oldHeight != self.MinHeight:
            self.LayoutChanged()

    def _get_color_vector(self, cid):
        """
        Get a color vector from a color ID.
        :param cid : The color ID
        :return    : c4d.Vector()
        """
        dic = self.GetColorRGB(cid)
        if dic:
            return c4d.Vector(float(dic['r']) * self.ColScale,
                              float(dic['g']) * self.ColScale,
                              float(dic['b']) * self.ColScale)
        else:
            return c4d.Vector()

if __name__ == "__main__":
    dlg = ExampleDialog()
    dlg.Open(c4d.DLG_TYPE_ASYNC, defaultw=400, defaulth=400)

Hi,

a bilinear interpolation is quite straight forward. If you have the quadrilateral Q with the the points,

c---d
|   |
a---b

then the bilinear interpolation is just,

ab = lerp(a, b, t0)
cd = lerp(c, d, t0)
res = lerp(ab, cd, t1)

where t0, t1 are the interpolation offset(s), i.e. the texture coordinates in your case (the ordering/orientation of the quad is obviously not set in stone). I am not quite sure what you do when rendering normals, but when you render a color gradient, in a value noise for example, you actually want to avoid linear interpolation, because it will give you these ugly star-patterns. So you might need something like a bi-quadratic, bi-cubic or bi-cosine interpolation, i.e. pre-interpolate your interpolation offsets.

If I am not overlooking something, this should also work for triangles when you treat them as quasi-quadrilaterals like Cinema does in its polygon type.

Cheers,
zipit

Hi @bentraje,

thank you for reaching out to us. As @Cairyn already said, there is little which prevents you from writing your own cloner. Depending on the complexity of the cloner, this can however be quite complex. Just interpolating between two positions or placing objects in a grid array is not too hard. But recreating all the complexity of a MoGraph cloner will be. It is also not necessary. Here are two more straight forward solutions:

1. As I said in the last thread (the one you did link), MoGraph is perfectly capable of driving arbitrary parameters of an object. I overlooked in the old thread that you did ask what I meant with ""drive the attributes of an object or its material"", so the file cube_bend_mograph.c4d shows you how you can drive the strength parameter of a bend object with MoGraph. The difference I then made was that while you cannot drive such attributes directly via the particle (arrays), but you can let MoGraphs interpolation system take care of it. Please keep in mind that I am everything but an expert for MoGraph. There are probably more elegant solutions for all this, but all this is out of scope for this forum. Please contact technical support or refer to Cineversity for questions about MoGraph.
2. One problem of MoGraph is that driving more than one arbitrary parameter of an object is a bit tedious. Since MoGraph's sole principle is interpolation and it can only interpolate on a single axis (between parameters), you will then have to start interpolating between two cloners to drive a second, third, fourth, etc. parameter. Here it would make sense to write a custom solution to have less complicated setups. Rather than rewriting a cloner, it would be however more sensible to just modify the cache of a cloner. This will only work when the cloner is in the "Instance Mode" "Instance", as otherwise the cache will only contain the instance wrappers (a bit confusing the naming here ^^). You could do this all inside a GVO, including building the cloner and its cache, but I did provide here a solution which relies on linking a cloner whose cache one wishes to modify. The idea is then simple, walk over all bend objects in the cache and modify their bend strength. You can find a scene file and the code below.

Cheers,
Ferdinand

file: cube_bend_python.c4d
code:

"""Example for modifying the cache of a node and returning it as the output
of a generator.

This specific example drives the bend strength of bend objects contained in
a Mograph cloner object. The example is designed for a Python generator 
object with a specific set of user data values. Please use the provided c4d
file if possible.

Note:
    This example makes use of the function `CacheIterator()` for cache 
    iteration which has been proposed on other threads for the task of walking
    a cache, looking for specific nodes. One can pass in one or multiple type
    symbols for the node types to be retrieved from the cache. I did not 
    unpack the topic of caches here any further.

    We are aware that robust cache walking can be a complex subject and 
    already did discuss adding such functionality to the SDK toolset in the
    future, but for now users have to do that on their own.

As discussed in:
    plugincafe.maxon.net/topic/13275/
"""

import c4d

# The cookie cutter cache iterator template, can be treated as a black-box,
# as it has little to do with the threads subject.
def CacheIterator(op, types=None):
    """An iterator for the elements of a BaseObject cache.

    Handles both "normal" and deformed caches and has the capability to 
    filter by node type.

    Args:
        op (c4d.BaseObject): The node to walk the cache for.
        types (Union[list, tuple, int, None], optional): A collection of type
         IDs from one of which a yielded node has to be derived from. Will
         yield all node types if None. Defaults to None.

    Yields:
        c4d.BaseObject: A cache element of op.

    Raises:
        TypeError: On argument type violations.
    """
    if not isinstance(op, c4d.BaseObject):
        msg = "Expected a BaseObject or derived class, got: {0}"
        raise TypeError(msg.format(op.__class__.__name__))

    if isinstance(types, int):
        types = (types, )
    if not isinstance(types, (tuple, list, type(None))):
        msg = "Expected a tuple, list or None, got: {0}"
        raise TypeError(msg.format(types.__class__.__name__))

    # Try to retrieve the deformed cache of op.
    temp = op.GetDeformCache()
    if temp is not None:
        for obj in CacheIterator(temp, types):
            yield obj

    # Try to retrieve the cache of op.
    temp = op.GetCache()
    if temp is not None:
        for obj in CacheIterator(temp, types):
            yield obj

    # If op is not a control object.
    if not op.GetBit(c4d.BIT_CONTROLOBJECT):
        # Yield op if it is derived from one of the passed type symbols.
        if types is None or any([op.IsInstanceOf(t) for t in types]):
            yield op

    # Walk the hierarchy of the cache.
    temp = op.GetDown()
    while temp:
        for obj in CacheIterator(temp, types):
            yield obj
        temp = temp.GetNext()


def main():
    """
    """
    # The user data.
    node = op[c4d.ID_USERDATA, 1]
    angle = op[c4d.ID_USERDATA, 2]
    fieldList = op[c4d.ID_USERDATA, 3]

    # Lazy parameter validation ;)
    if None in (node, angle, fieldList):
        raise AttributeError("Non-existent or non-populated user data.")

    # Get the cache of the node and clone it (so that we have ownership).
    cache = node.GetDeformCache() or node.GetCache()
    if cache is None:
        return c4d.BaseObject(c4d.Onull)
    clone = cache.GetClone(c4d.COPYFLAGS_NONE)

    # Iterate over all bend objects in the cache ...
    for bend in CacheIterator(clone, c4d.Obend):
        # ..., sample the field list for the bend object position, ...
        fieldInput = c4d.modules.mograph.FieldInput([bend.GetMg().off], 1)
        fieldOutput = fieldList.SampleListSimple(op, fieldInput,
                                                 c4d.FIELDSAMPLE_FLAG_VALUE)
        if (not isinstance(fieldOutput, c4d.modules.mograph.FieldOutput) or
                fieldOutput.GetCount() < 1):
            raise RuntimeError("Error sampling field input.")
        # ... and set the bend strength with that field weight as a multiple 
        # of the angle defined in the user data.
        bend[c4d.DEFORMOBJECT_STRENGTH] = angle * fieldOutput.GetValue(0)

    # Return the clone's cache.
    return clone

Hello @shetal,

thank you for reaching out to us. The reformulation of your question and the conformance with the forum guidelines on tagging is also much appreciated.

About your question: As stated in the forum guidelines, we cannot provide full solutions for questions, but provide answers for specific questions. Which is why I will not show here any example code, the first step would have to be made by you. I will instead roughly line out the purpose of and workflow around VideoPostData, which I assume is what you are looking for anyway.

VideoPostData is derived from NodeData, the base class to implement a node for a classic API scene graph. Node means here 'something that lives inside a document and is an addressable entity', examples for such nodes are materials, shaders, objects, tags, ..., and as such 'video post' node. As mentioned in its class description, VideoPostData is a versatile plugin interface which can be used to intervene a rendering process in multiple ways. The most tangible place for VideoPostData in the app is the render settings where video post plugins can be added as effects for a rendering process as shown below with the built-in water mark video post node.

VideoPostData is an effect, meaning that you cannot use it to invoke a rendering process and on its own it also cannot forcibly add itself to a rendering and must be included manually with the RenderData, the render settings of a rendering. However, a user could make a render setting which includes such watermark effect part of his or her default render settings. One could also implement another plugin interface, SceneHookData, to automatically add such effect to every active document. We would not encourage that though, as this could be confusing or infuriating for users. Finally, such VideoPostData plugin would be visible by default like all NodeData plugins, i.e., it would appear as something in menus that the user can add and interact with. To prevent this if desired, one would have to register the plugin with the flag PLUGINFLAG_HIDE suppress it from popping up in the 'Effect ...' button menu. I cannot tell you with certainty if it is possible to hide programmatically added effect nodes from the users view in the effect list of a render settings. There are some flags which can be used to hide instances of nodes, but I would have to test myself if this also applies in this list, it is more likely that this will not be possible.

To implement a VideoPostData plugin interface, one can override multiple methods and take different approaches, the most commonly used one is to override VideoPostData::Execute(Link) which will be called multiple times for each rendered frame. The method follows a flag/message logic which is commonly used in Cinema 4D's classic API, where one gets passed in a flag which signalizes in which context the method is being called. Here the context is at which state of the rendering this call is being made, and the chain is:

• VIDEOPOSTCALL::FRAMESEQUENCE - Series of images starts.
• VIDEOPOSTCALL::FRAME - Image render starts.
• VIDEOPOSTCALL::SUBFRAME - Sub-frame starts.
• VIDEOPOSTCALL::RENDER - Render precalculation.
• VIDEOPOSTCALL::INNER - Render precalculation.
• VIDEOPOSTCALL::INNER - Immediately after rendering.
• VIDEOPOSTCALL::RENDER - Immediately after shader cleanup.
• VIDEOPOSTCALL::SUBFRAME - Sub-frame rendering done.
• VIDEOPOSTCALL::FRAME - Frame rendering done.
• VIDEOPOSTCALL::FRAMESEQUENCE - Complete rendering process finished.

These flags are accompanied by information if the flags denotes the opening or closing of that 'step' in the rendering process. A developer often then restricts its plugin functionality to a certain flag. I.e., in your case you only want to execute some code when the closing VIDEOPOSTCALL::FRAME is being passed, i.e., after a single frame and all its sub-frames have been rendered. Execute() also passes in a pointer to a VideoPostStruct(Link) which carries information about the ongoing rendering. One of its fields is render, a pointer to a Render(Link). This data structure represents a rendering with multiple buffers and provides the method GetBuffer() which returns a pointer to VPBuffer buffer. In your case you would want to retrieve the RGBA buffer for the rendering by requesting the VPBUFFER_RGBA buffer (Link) with GetBuffer().

This buffer is then finally the pixel buffer, the bitmap data you want to modify. The buffer is being read and written in a line wise fashion with VPBuffer::GetLine() and ::SetLine(). Here you would have to superimpose your watermark information onto the frame. I would do this in a shader like fashion, i.e., write a function which I can query for a texture coordinate for every pixel/fragment in every line and it will then return an RBGA value which I could then combine with the RGBA information which is in the buffer at that coordinate. The details on that depend on what you want to do, e.g.,

• Should the watermark be tiled across the frame or just live in a 'corner'?
• Should it contain alpha information?
• Can the user influence it, or is it just a png file on disk?
• etc...

and the answers to that are mostly algorithmic and not directly connected to our API which limits the amount of support we can provide for them. If this all sounds very confusing to you, it might be helpful to look at our video post examples I did post in the previous thread, e.g., vpreconstructimage.cpp, as this will probably make things less daunting.

If you decide that you do not want to take this route for technical or complexity reasons, you could write a SceneHookData plugin which listens via NodeData::Message for MSG_MULTI_RENDERNOTIFICATION(Link), a message family which is being sent in the context of a rendering. There you would have to evaluate the start field in the RenderNotificationData(Link) accompanying the message, to determine if the call is for the start or end of a rendering. Then you could grab the rendering output file(s) on disk with the help of the render settings from disk and 'manually' superimpose your watermark information. This will come with the drawback that you might have to deal with compressed video files like mpeg or Avi and all the image formats. Some complexity in that can be hidden away with our BaseBitmap type I did mention in my last posting, but not all of it. There is also the fact that you might run into problems when this plugin runs on a render server, where you cannot easily obtain write or even read access to files of the render output.

I hope this give you some desired guidance,
Ferdinand

Dear community,

The following code example demonstrates how to discover the channel identifiers of the "Channel" parameter of a Substance shader, so that the channel can be changed programmatically for a substance asset unknown at the time of writing the script.

This question reached us via mail, but since answering it requires no confidential data, we are sharing the solution here. The "trick" is to traverse the description of the shader, as these identifiers depend on the substance.

Cheers,
Ferdinand

The result (the example script will randomly select a channel, but with the data provided, channels can also be selected by their name or a substring match as for example "diffuse"):

The code:

"""Example for discovering the channels of a Substance shader.

The solution is a bit hacky by traversing the description of the shader but should work.
"""

import c4d
import random

def GetSubstanceChannels(shader: c4d.BaseShader) -> dict[int:str]:
    """Returns all channels of the substance loaded into #shader as a dictionary of id-label pairs.
    """
    if not isinstance(shader, c4d.BaseShader) or (shader.GetType() != c4d.Xsubstance):
        raise TypeError(f"{shader} is not a substance shader.")

    # Get the data for the "Channel" dropdown element from the description of the shader.
    description = shader.GetDescription(c4d.DESCFLAGS_DESC_NONE)
    channelData = description.GetParameter(c4d.SUBSTANCESHADER_CHANNEL)

    # Get the elements in the drop down menu.
    elements = channelData[c4d.DESC_CYCLE]
    if not isinstance(elements, c4d.BaseContainer):
        raise RuntimeError(f"Could not access Channel parameter description in {shader}.")
    
    # Pack the data into a dictionary and return it.
    return {id: label for id, label in elements}

def main(doc: c4d.documents.BaseDocument):
    """
    """
    # Get the active material.
    material = doc.GetActiveMaterial()
    if not isinstance(material, c4d.BaseMaterial):
        raise RuntimeError("Please select a material.")

    # Get the substance shader loaded into the color channel of the material.
    shader = material[c4d.MATERIAL_COLOR_SHADER]
    channelData = GetSubstanceChannels(shader)

    for id, label in channelData.items():
        print (f"id: {id}, label: {label}")

    # To select a specific channel, one would have to do a string comparison here to find keywords as
    # "Color" or "Metal" in the channel label. I am just randomly selecting a channel instead.
    channelId = random.choice(tuple(channelData.keys()))
    channelLabel = channelData[channelId]
    print (f"Setting substance to channel '{channelLabel}({channelId})'")
    shader[c4d.SUBSTANCESHADER_CHANNEL] = channelId

    c4d.EventAdd()

if __name__=='__main__':
    main(doc)

Hello @joel,

Thank you for reaching out to us. Yeah, the GUI examples for Python are in a bit rough state. I would recommend having a look at the C++ Docs, as they cover more ground.

• C ++ Resource File Manual.
• A very basic Python dialog example

There are in principal two ways to define GUIs in Cinema 4D, dialogs and descriptions (see the C++ Manual for details). Dialogs are primarily used for things like CommandData plugins, i.e., when you need a separate window. NodeData plugins (an object, material, shader, tag, etc.) use description resources to define their GUIs and are displayed in the Attribute Manger.

I should really find the time to write a new GUI manual both for C++ and Python, we are aware that it is urgent, but I never got to it yet, because it will be quite some undertaking. But I have written a little example for your specific case, in the hopes that it will help you. It goes over some basic and more advanced techniques:

• How to bind a CommandData plugin and a GeDialog together.
• What the major overwritable methods do.
• How GeDialog.CreateLayout works.
• Using custom GUIs
• Implementing a (very simple) data model for a dialog.

Cheers,
Ferdinand

The result:

The code:

"""Implements a CommandData plugin with dialog with a dynamic GUI, using multiple CUSTOMGUI_LINKBOX
gadgets.

Save this file as "someName.pyp" and target Cinema 4D's plugin directory list to the directory
containing the file "someName.pyp". The plugin will appear as "Dialog Manager Command" in the
"Extensions" menu.
"""

import c4d
import typing


class MyDialog(c4d.gui.GeDialog):
    """Implements a dialog with link box gadgets which can be dynamically added and removed at
    runtime.

    This also demonstrates how one can put an abstraction layer / data model (or however one wants
    to call such thing) on top of a couple of gadgets, here the link box GUIs.
    """
    # The gadget IDs of the dialog.

    # The three groups.
    ID_GRP_MAIN: int = 1000
    ID_GRP_ELEMENTS: int = 1001
    ID_GRP_BUTTONS: int = 1002

    # The three buttons at the bottom.
    ID_BTN_ADD: int = 2000
    ID_BTN_REMOVE: int = 2001
    ID_BTN_PRINT: int = 2002

    # The dynamic elements. They start at 3000 and then go NAME, LINK, NAME, LINK, ...
    ID_ELEMENTS_START: int = 3000
    ID_ELEMENT_NAME: int = 0
    ID_ELEMENT_LINK: int = 1

    # A default layout flag for GUI gadgets and a default gadget spacing.
    DEFAULT_FLAGS: int = c4d.BFH_SCALEFIT | c4d.BFV_SCALEFIT
    DEFAULT_SPACE: tuple[int] = (5, 5, 5, 5)

    # A settings container for a LinkBoxGui instance, these are all default settings, so we could
    # pass the empty BaseContainer instead with the same effect. But here you can tweak the settings
    # of a custom GUI. Since we want all link boxes to look same, this is done as a class constant.
    LINKBOX_SETTINGS: c4d.BaseContainer = c4d.BaseContainer()
    LINKBOX_SETTINGS.SetBool(c4d.LINKBOX_HIDE_ICON, False)
    LINKBOX_SETTINGS.SetBool(c4d.LINKBOX_LAYERMODE, False)
    LINKBOX_SETTINGS.SetBool(c4d.LINKBOX_NO_PICKER, False)
    LINKBOX_SETTINGS.SetBool(c4d.LINKBOX_NODE_MODE, False)

    def __init__(self, items: list[c4d.BaseList2D] = []) -> None:
        """Initializes a MyDialog instance.

        Args:
            items (list[c4d.BaseList2D]): The items to init the dialog with.
        """
        super().__init__()

        self._items: list[c4d.BaseList2D] = []  # The items linked in the dialog.
        self._doc: typing.Optional[c4d.documents.BaseDocument] = None  # The document of the dialog.
        self._hasCreateLayout: bool = False  # If CrateLayout() has run for the dialog or not.

        # Bind the dialog to the passed items.
        self.Items = items

    # Our data model, we expose _items as a property, so that we can read and write items from
    # the outside. For basic type gadgets, e.g., string, bool, int, float, etc., there are
    # convenience methods attached to GeDialog like Get/SetString. But there is no GetLink() method.
    # So one must do one of two things:
    #
    #   1. Store all custom GUI gadgets in a list and manually interact with them.
    #   2. Put a little abstraction layer on top of things as I did here.
    #
    # Calling myDialogInstance.Items will always yield all items in the order as shown in the GUI,
    # and calling my myDialogInstance.Items = [a, b, c] will then show them items [a, b, c] in three
    # link boxes in the dialog. No method is really intrinsically better, but I prefer it like this.
    @property
    def Items(self) -> list[c4d.BaseList2D]:
        """gets all items linked in the link boxes.
        """
        return self._items

    @Items.setter
    def Items(self, value: list[c4d.BaseList2D]) -> None:
        """Sets all items linked in link boxes.
        """
        if not isinstance(value, list):
            raise TypeError(f"Items: {value}")

        # Set the items and get the associated document from the first item.
        self._items = value
        self._doc = value[0].GetDocument() if len(self._items) > 0 else None

        # Update the GUI when this setter is being called after CreateLayout() has already run.
        if self._hasCreateLayout:
            self.PopulateDynamicGroup(isUpdate=True)

    def InitValues(self) -> bool:
        """Called by Cinema 4D once CreateLayout() has ran.

        Not needed in this case.
        """
        return super().InitValues()

    def CreateLayout(self) -> bool:
        """Called once by Cinema 4D when a dialog opens to populate the dialog with gadgets.

        But one is not bound to adding only items from this method, a dialog can be repopulated
        dynamically.
        """
        self._hasCreateLayout = True
        self.SetTitle("Dialog Manager Command")

        # The outmost layout group of the dialog. It has one column and we will only place other
        # groups in it. Items are placed like this:
        #
        #   Main {
        #       a,
        #       b,
        #       c,
        #       ...
        #   }
        #
        self.GroupBegin(id=self.ID_GRP_MAIN, flags=c4d.BFH_SCALEFIT | c4d.BFV_SCALEFIT, cols=1)
        # Set the group spacing of ID_GRP_MAIN to (5, 5, 5, 5)
        self.GroupBorderSpace(*self.DEFAULT_SPACE)

        # An layout group inside #ID_GRP_MAIN, it has two columns and we will place pairs of
        # labels and link boxes in it. The layout is now:
        #
        #   Main {
        #       Elements {
        #           a, b,
        #           c, d,
        #           ... }
        #       b,
        #       c,
        #       ...
        #   }
        #
        self.GroupBegin(id=self.ID_GRP_ELEMENTS, flags=c4d.BFH_SCALEFIT | c4d.BFV_SCALEFIT, cols=2)
        # Set the group spacing of ID_GRP_ELEMENTS to (5, 5, 5, 5).
        self.GroupBorderSpace(*self.DEFAULT_SPACE)
        # Call our PopulateDynamicGroup() method, here with isUpdate=False, so that group
        # ID_GRP_ELEMENTS won't be flushed the first time its is being built. Doing this is the same
        # as moving all the code from PopulateDynamicGroup() to the line below.
        self.PopulateDynamicGroup(isUpdate=False)
        self.GroupEnd()  # ID_GRP_ELEMENTS

        # A second layout group inside ID_GRP_MAIN, its has three columns and will place our buttons
        # in it. The layout is now:
        #
        #   Main {
        #       Elements {
        #           a, b,
        #           c, d,
        #           ... }
        #       Buttons {
        #           a, b, c,
        #           e, f, g,
        #           ...},
        #       c,
        #       ...
        #   }
        #
        self.GroupBegin(id=self.ID_GRP_BUTTONS, flags=c4d.BFH_SCALEFIT, cols=3)
        self.GroupBorderSpace(*self.DEFAULT_SPACE)
        # The three buttons.
        self.AddButton(id=self.ID_BTN_ADD, flags=c4d.BFH_SCALEFIT, name="Add Item")
        self.AddButton(id=self.ID_BTN_REMOVE, flags=c4d.BFH_SCALEFIT, name="Remove Last Item")
        self.AddButton(id=self.ID_BTN_PRINT, flags=c4d.BFH_SCALEFIT, name="Print Items")
        self.GroupEnd()  # ID_GRP_BUTTONS

        self.GroupEnd()  # ID_GRP_MAIN

        return super().CreateLayout()

    def PopulateDynamicGroup(self, isUpdate: bool = False):
        """Builds the dynamic part of the GUI.

        This is a custom method that is not a member of GeDialog.

        Args:
            isUpdate (bool, optional): If this is an GUI update event. Defaults to False.

        Raises:
            MemoryError: On gadget allocation failure.
            RuntimeError: On linking objects failure.
        """
        # When this is an update event, i.e., the group #ID_GRP_ELEMENTS has been populated before,
        # flush the items in the group and set the gadget insertion pointer of the this dialog to
        # the start of #ID_GRP_ELEMENTS. Everything else done in CreateLayout(), the groups, the
        # buttons, the spacings, remains intact.
        if isUpdate:
            self.LayoutFlushGroup(self.ID_GRP_ELEMENTS)

        # For each item in self._items ...
        for i, item in enumerate(self.Items):
            # Define the current starting id: 3000, 3002, 3004, 3006, ...
            offset: int = self.ID_ELEMENTS_START + (i * 2)

            # Add a static text element containing the class name of #item or "Empty" when the
            # item is None.
            self.AddStaticText(id=offset + self.ID_ELEMENT_NAME,
                               flags=c4d.BFH_LEFT,
                               name=item.__class__.__name__ if item else "Empty")

            # Add a link box GUI, a custom GUI is added by its gadget ID, its plugin ID, here
            # CUSTOMGUI_LINKBOX, and additionally a settings container, here the constant
            # self.LINKBOX_SETTINGS.
            gui: c4d.gui.LinkBoxGui = self.AddCustomGui(
                id=offset + self.ID_ELEMENT_LINK,
                pluginid=c4d.CUSTOMGUI_LINKBOX,
                name="",
                flags=c4d.BFH_SCALEFIT,
                minw=0,
                minh=0,
                customdata=self.LINKBOX_SETTINGS)
            if not isinstance(gui, c4d.gui.LinkBoxGui):
                raise MemoryError("Could not allocate custom GUI.")

            # When item is not a BaseList2D, i.e., None, we do not have to set the link.
            if not isinstance(item, c4d.BaseList2D):
                continue

            # Otherwise try to link #item in the link box GUI.
            if not gui.SetLink(item):
                raise RuntimeError("Failed to set node link from data.")

        if isUpdate:
            self.LayoutChanged(self.ID_GRP_ELEMENTS)

    def AddEmptyItem(self) -> None:
        """Adds a new empty item to the data model and updates the GUI.

        This is a custom method that is not a member of GeDialog.
        """
        self._items.append(None)
        self.PopulateDynamicGroup(isUpdate=True)

    def RemoveLastItem(self) -> None:
        """Removes the last item from the data model and updates the GUI.

        This is a custom method that is not a member of GeDialog.
        """
        if len(self._items) > 0:
            self._items.pop()
            self.PopulateDynamicGroup(isUpdate=True)

    def UpdateItem(self, cid: int):
        """Updates an item in list of link boxes.

        This is a custom method that is not a member of GeDialog.

        Args:
            cid (int): The gadget ID for which this event was fired (guaranteed to be a link box
                GUI gadget ID unless I screwed up somewhere :D).

        """
        # The index of the link box and therefore index in self._items, e.g., the 0, 1, 2, 3, ...
        # link box GUI / item.
        index: int = int((cid - self.ID_ELEMENTS_START) * 0.5)

        # Get the LinkBoxGui associated with the ID #cid.
        gui: c4d.gui.LinkBoxGui = self.FindCustomGui(id=cid, pluginid=c4d.CUSTOMGUI_LINKBOX)
        if not isinstance(gui, c4d.gui.LinkBoxGui):
            raise RuntimeError(f"Could not access link box GUI for gadget id: {cid}")

        # Retrieve the item in the link box gui. This can return None, but in this case we are
        # okay with that, as we actually want to reflect in our data model self._items when
        # link box is empty. The second argument to GetLink() is a type filter. We pass here
        # #Tbaselist2d to indicate that we are interested in anything that is a BaseList2D. When
        # would pass Obase (any object), and the user linked a material, the method would return
        # None. If we would pass Ocube, only cube objects would be retrieved.
        item: typing.Optional[c4d.BaseList2D] = gui.GetLink(self._doc, c4d.Tbaselist2d)

        # Write the item into our data model and update the GUI.
        self.Items[index] = item
        self.PopulateDynamicGroup(isUpdate=True)

    def PrintItems(self) -> None:
        """Prints all items held by the dialog to the console.

        This is a custom method that is not a member of GeDialog.
        """
        for item in self.Items:
            print(item)

    def Command(self, cid: int, msg: c4d.BaseContainer) -> bool:
        """Called by Cinema 4D when the user interacts with a gadget.

        Args:
            cid (int): The id of the gadget which has been interacted with.
            msg (c4d.BaseContainer): The command data, not used here.

        Returns:
            bool: Success of the command.
        """
        # You could also put a lot of logic into this method, but for an example it might be better
        # to separate out the actual logic into methods to make things more clear.

        # The "Add Item" button has been clicked.
        if cid == self.ID_BTN_ADD:
            self.AddEmptyItem()
        # The "Remove Item" button has been clicked.
        elif cid == self.ID_BTN_REMOVE:
            self.RemoveLastItem()
        # The "Print Items" button has been clicked.
        elif cid == self.ID_BTN_PRINT:
            self.PrintItems()
        # One of the link boxes has received an interaction.
        elif (cid >= self.ID_ELEMENTS_START and (cid - self.ID_ELEMENTS_START) % 2 == self.ID_ELEMENT_LINK):
            self.UpdateItem(cid)

        return super().Command(cid, msg)

    def CoreMessage(self, cid: int, msg: c4d.BaseContainer) -> bool:
        """Called by Cinema 4D when a core event occurs.

        You could use this to automatically update the dialog when the selection state in the 
        document has changed. I did not flesh this one out.
        """
        # When "something" has happened in the, e.g., the selection has changed ...
        # if cid == c4d.EVMSG_CHANGE:
        # items: list[c4d.BaseList2D] = (
        #     self._doc.GetSelection() + self._doc.GetActiveMaterials() if self._doc else [])

        # newItems: list[c4d.BaseList2D] = list(n for n in items if n not in self._items)
        # self.Items = self.Items + newItems

        return super().CoreMessage(cid, msg)


class DialogManagerCommand (c4d.plugins.CommandData):
    """Provides an implementation for a command data plugin with a foldable dialog.

    This will appear as the entry "Dialog Manager Command" in the extensions menu.
    """
    ID_PLUGIN: int = 1060264  # The plugin ID of the command plugin.
    REF_DIALOG: typing.Optional[MyDialog] = None  # The dialog hosted by the plugin.

    def GetDialog(self, doc: typing.Optional[c4d.documents.BaseDocument] = None) -> MyDialog:
        """Returns a class bound MyDialog instance.

        Args:
            doc (typing.Optional[c4d.documents.BaseDocument], optional): The active document. 
                Defaults to None.

        This is a custom method that is not a member of CommandData.
        """
        # Get the union of all selected objects, tags, and materials in #doc or define the empty
        # list when doc is None. Doing it in this form is necessary, because GetState() will call
        # this method before Execute() and we only want to populate the dialog when the user invokes
        # the command.
        items: list[c4d.BaseList2D] = doc.GetSelection() + doc.GetActiveMaterials() if doc else []

        # Instantiate a new dialog when there is none.
        if self.REF_DIALOG is None:
            self.REF_DIALOG = MyDialog(items)
        # Update the dialog state when the current document selection state is different. This will
        # kick in when the user selects items, opens the dialog, closes the dialog, and changes the
        # selection. This very much a question of what you want, and one could omit doing this or
        # do it differently.
        elif doc is not None and self.REF_DIALOG.Items != items:
            self.REF_DIALOG.Items = items

        # Return the dialog instance.
        return self.REF_DIALOG

    def Execute(self, doc: c4d.documents.BaseDocument) -> bool:
        """Folds or unfolds the dialog.
        """
        # Get the dialog bound to this command data plugin type.
        dlg: MyDialog = self.GetDialog(doc)
        # Fold the dialog, i.e., hide it if it is open and unfolded.
        if dlg.IsOpen() and not dlg.GetFolding():
            dlg.SetFolding(True)
        # Open or unfold the dialog.
        else:
            dlg.Open(c4d.DLG_TYPE_ASYNC, self.ID_PLUGIN)

        return True

    def RestoreLayout(self, secret: any) -> bool:
        """Restores the dialog on layout changes.
        """
        return self.GetDialog().Restore(self.ID_PLUGIN, secret)

    def GetState(self, doc: c4d.documents.BaseDocument) -> int:
        """Sets the command icon state of the plugin.

        With this you can tint the command icon blue when the dialog is open or grey it out when
        some condition is not met (not done here). You could for example disable the plugin when
        there is nothing selected in a scene, when document is not in polygon editing mode, etc.
        """
        # The icon is never greyed out, the button can always be clicked.
        result: int = c4d.CMD_ENABLED

        # Tint the icon blue when the dialog is already open.
        dlg: MyDialog = self.GetDialog()
        if dlg.IsOpen() and not dlg.GetFolding():
            result |= c4d.CMD_VALUE

        return result


def RegisterDialogManagerCommand() -> bool:
    """Registers the example.
    """
    # Load one of the builtin icons of Cinema 4D as the icon of the plugin, you can browse the
    # builtin icons under:
    #   https://developers.maxon.net/docs/py/2023_2/modules/c4d.bitmaps/RESOURCEIMAGE.html
    bitmap: c4d.bitmaps.BaseBitmap = c4d.bitmaps.InitResourceBitmap(c4d.Tdisplay)

    # Register the plugin.
    return c4d.plugins.RegisterCommandPlugin(
        id=DialogManagerCommand.ID_PLUGIN,
        str="Dialog Manager Command",
        info=c4d.PLUGINFLAG_SMALLNODE,
        icon=bitmap,
        help="Opens a dialog with scene element link boxes in it.",
        dat=DialogManagerCommand())


# Called by Cinema 4D when this plugin module is loaded.
if __name__ == '__main__':
    if not RegisterDialogManagerCommand():
        raise RuntimeError(
            f"Failed to register {DialogManagerCommand} plugin.")

Dear Community,

this is our answer

1. Why is c4d.C4DPL_BUILDMENU fired 4 times, instead of once?

In general, we do not make any promises regarding messages being emitted only once or things not being None \ nullptr. When there are any guarantees, the message or function description will explicitly say so. The recent change in behavior is caused by the menu being dynamically rebuilt by Cinema 4D.

2. If we react to the first pluginMessage only (→ same time in startup sequence), why is R26 behaving differently?

I am not quite sure how you mean that, what do you mean by first? Are you using a module attribute like, for example, didBuiltMenu? Your code did not show this. You could use a module attribute, and this would mostly work, as *.pyp plugin modules are persistent, but reloading the Python plugins will throw a wrench into things. I personally would simply check for the existence of a menu item by title.

3. Is there something like executedDelayed(), so that we can execute Python code at the very end of the startup sequence, after the UI initialization has been finished?

There are multiple phases in the lifecycle of a Cinema 4D instance, they are all documented under PluginMessage. When you want to update the menu outside of C4DPL_BUILDMENU, you must call c4d.gui.UpdateMenus() after the changes.

But this all seems a bit too complicated for the task IMHO. Simply search for the menu entry you want to add, e. g., My Menu, and stop operations when it already does exist. You could also make this more complicated and index based, so that you can distinguish two menus called My Menu. You could also flush and update existing menus, in the end, menus are just an instance of c4d.BaseContainer. You can more or less do what you want.

Find a simple example for your problem below.

Cheers,
Ferdinand

Result:

The code (must be saved as a pyp file):

"""Demonstrates adding and searching menu entries.
"""

import c4d
import typing

# A type alias for a menu data type used by the example, it is just easier to define a menu as
# JSON/a dict, than having to write lengthy code.
MenuData: typing.Type = dict[str, typing.Union[int, 'MenuData']]

# Define the menu which should be inserted. The data does not carry a title for the root of the
# menu, it will be defined by the #UpdateMenu call. All dictionaries are expanded (recursively) 
# into sub-menus and all integer values will become commands. The keys for commands do not matter
# in the sense that Cinema 4D will determine the label of a menu entry, but they are of course 
# required for the dictionary. For older version of Cinema 4D, you will have to use #OrderedDict,
# as ordered data for #dict is a more recent feature of Python (3.7 if I remember correctly).
MENU_DATA: MenuData = {
    "Objects": {
        "0": c4d.Ocube,
        "1": c4d.Osphere,
        "Splines": {
            "0": c4d.Osplinecircle,
            "1": c4d.Osplinerectangle
        }
    },
    "0": 13957, # Clear console command
    # "1": 12345678 # Your plugin command
}

def UpdateMenu(root: c4d.BaseContainer, title: str, data: MenuData, forceUpdate: bool = False) -> bool:
    """Adds #data to #root under a menu entry called #title when there is not yet a menu entry 
    called #title.

    When #forceUpdate is true, the menu of Cinema 4D will be forced to update to the new state 
    outside of C4DPL_BUILDMENU.
    """
    def doesContain(root: c4d.BaseContainer, title: str) -> bool:
        """Tests for the existence of direct sub containers with #title in #root.

        One could also use #c4d.gui.SearchMenuResource, this serves more as a starting point if one
        wants to customize this (search for a specific entry among multiple with the same title,
        flushing an entry, etc.).
        """
        # BaseContainer can be iterated like dict.items(), i.e., it yields keys and values.
        for _, value in root:
            if not isinstance(value, c4d.BaseContainer):
                continue
            elif value.GetString(c4d.MENURESOURCE_SUBTITLE) == title:
                return True
        
        return False
    
    def insert(root: c4d.BaseContainer, title: str, data: MenuData) -> c4d.BaseContainer:
        """Inserts #data recursively under #root under the entry #title.
        """
        # Create a new container and set its title.
        subMenu: c4d.BaseContainer = c4d.BaseContainer()
        subMenu.InsData(c4d.MENURESOURCE_SUBTITLE, title)

        # Iterate over the values in data, insert commands, and recurse for dictionaries.
        for key, value in data.items():
            if isinstance(value, dict):
                subMenu = insert(subMenu, key, value)
            elif isinstance(value, int):
                subMenu.InsData(c4d.MENURESOURCE_COMMAND, f"PLUGIN_CMD_{value}")
        
        root.InsData(c4d.MENURESOURCE_SUBMENU, subMenu)
        return root

    # #title is already contained in root, we get out. You could also fashion the function so
    # that is clears out an existing entry instead of just reporting its existence, but I did not
    # do that here.
    if doesContain(root, title):
        return False

    # Update #root and force a menu update when so indicated by the user.
    insert(root, title, data)
    if forceUpdate and c4d.threading.GeIsMainThreadAndNoDrawThread():
        c4d.gui.UpdateMenus()

    return True


def PluginMessage(mid: int, data: typing.Any) -> bool:
    """Updates the menu with some menu data only once when C4DPL_BUILDMENU is emitted.
    """
    if mid == c4d.C4DPL_BUILDMENU:
        # Get the whole menu of Cinema 4D an insert #MENU_DATA under a new entry "MyMenu"
        menu: c4d.BaseContainer = c4d.gui.GetMenuResource("M_EDITOR")
        UpdateMenu(root=menu, title="MyMenu", data=MENU_DATA)

def SomeFunction():
    """Can be called at any point to update the menu, as long as the call comes from the main
    thread (and is not a drawing thread).
    """
    # Get the whole menu of Cinema 4D an insert #MENU_DATA under a new entry "MyMenu"
    menu: c4d.BaseContainer = c4d.gui.GetMenuResource("M_EDITOR")
    UpdateMenu(root=menu, title="MyMenu", data=MENU_DATA, forceUpdate=True)

if __name__ == "__main__":
    pass

Dear Community,

This question reached us via mail and since answering it does not require confidential information and since I thought others find this interesting too, I am sharing my answer here. The question was How to add enum values dynamically to a node attribute that uses an Enum GUI?".

Find my answer below.

Cheers,
Ferdinand

Result:

Code:

#include "c4d_basematerial.h"
#include "maxon/datadescription_nodes.h"
#include "maxon/graph.h"
#include "maxon/graph_helper.h"
#include "maxon/nodesgraph.h"
#include "maxon/nodesystem.h"

namespace maxon 
{
  /// @brief Demonstrates how to modify the enum values of an attribute.
  /// @details One place where one could do this is inside the #::InstantiateImpl method of a 
  /// #NodeTemplateInterface one is implementing so that every new node is being populated with
  /// enum values of our liking. But as demonstrated by the example below, nothing prevents us
  /// from doing the same thing at runtime on a graph.
  Result<void> AddEnumValues(BaseDocument* doc)
  {
    iferr_scope;
    
    // Get the active material's node graph and start a transaction.
    NodeMaterial* const material = static_cast<NodeMaterial*>(doc->GetActiveMaterial());
    CheckArgument(material);
    nodes::NodesGraphModelRef graph = material->GetGraph(GetActiveNodeSpaceId()) iferr_return;

    GraphTransaction transaction = graph.BeginTransaction() iferr_return;
    {
      // Get the mutable root for #graph. This way is not only shorter than first getting the
      // mutable node system for #graph and then its mutable root, but also the only way that
      // actually works here. We can do this because starting a transaction on a graph model also
      // implies modifying the node system. So, we do not have to call NodeSystem::BeginModification
      // in this case.
      nodes::MutableNode root = nodes::ToMutableNode(graph.GetRoot()) iferr_return;

      // Iterate over all children of the root to get hold of nodes which have our port.
      for (auto node : root.GetChildren())
      {
        // Attempt to get hold of our enum port.
        nodes::MutablePort enumPort = node.GetInputs().FindPort(
          Id("in@eSp1K8T8GNcuPwKSds8Lvs")) iferr_return;

        // We could also add a non-existing port here with MutableNode::AddPort
        if (!enumPort || !enumPort.IsValid())
          continue;

        // NodeTemplateInterface::InstantiateImpl code would start here.

        // Set the data type and label of the port, doing this is obviously optional.
        enumPort.SetType<String>() iferr_return;
        enumPort.SetValue(NODE::BASE::NAME, "My Enumeration"_s) iferr_return;

        // Build the enum data and write it into the port.
        BaseArray<Tuple<Id, Data>> entries;
        for (const Int32 i : {1, 2, 3, 4, 5})
        {
          const String data = FormatString("Item @", i);
          const Id id = Id::Create(label) iferr_return;
          entries.Append(Tuple<Id, Data>(id, data)) iferr_return;
        }

        DataDictionary enumPortData;
        enumPortData.Set(DESCRIPTION::DATA::BASE::ENUM, entries) iferr_return;
        enumPort.SetValue(nodes::PortDescriptionData, std::move(enumPortData)) iferr_return;

        // And set the default value of the port.
        enumPort.SetDefaultValue("Item 1"_s) iferr_return;
      }
    // Commit the transaction and with it the node system modification.
    } transaction.Commit() iferr_return;

    return OK;
  }
}

Hello @Gaal-Dornik,

Thank you for reaching out to us. And thank you @gheyret for your community answer.

@gheyret has already lined out some of the problems that come with creating a pie menu in Cinema 4D.

Do you know is there a way to show multiple ShowPopupDialog at once?

No, that is not possible, because a popup menu is intrinsically modal in Cinema 4D, i.e., blocking. So when you have this code,

a = c4d.gui.ShowPopupDialog(cd=None, bc=menuA, x=300, y=300)
b = c4d.gui.ShowPopupDialog(cd=None, bc=menuB, x=400, y=300)

the second line will only run once the user made a choice the first popup menu.

Maybe i can modify the existing M_GLOBAL_POPUP in Python?

You can do that with c4d.gui.SearchMenuResource, but I would strongly advise against doing that at runtime; at least when you do not specify what 'modify' means. You can sort of do it when C4DPL_BUILDMENU is emitted, but even there it is quite risky when you delete or move things.

Just appending things to existing menus is always fine, you can have a look at this thread for details.

How to Deal with This?

This is not the first time the question has been asked, and while @gheyret is correct in his analysis, an external UI is not the only solution.

1. Handle multiple dialogs in tandem. We before talked about this here. Below I provided a bit more detailed sketch for doing this. When you play around with this, you will see that my sketch is still quite error prone. You could tidy this up by writing more code, but this multiple dialogs in tandem thing is tricky to handle.
2. The alternative is draw the menu yourself into a viewport. The menu is therefore also restricted to viewports. There were multiple plugins in the past which have done this as commercial plugins. Here one of them had been discussed. The menu itself must be then a plugin hook which provides access to view port and is also allowed to manipulate the scene. ToolData is one choice, in C++ we can also use a SceneHookdata plugin.

Cheers,
Ferdinand

Result:

Code:

"""Realizes a dialog handler which handles multiple dialogs, primarily with the feature that closing
one dialog entails closing all of them.

Must be run in the script manager.
"""

import c4d
import math

__res__: c4d.plugins.GeResource = c4d.plugins.GeResource()
__res__.InitAsGlobal()

class RadialHandler:
    """Realizes the dialog handler object which controls multiple dialogs in a radial menu fashion.
    """
    def __init__(self) -> None:
        """Inits the handler.
        """
        self._collection: dict[MenuContainer, list[bool]] = {}

    def Open(self, position: tuple[int], radius: int = 200):
        """Open all dialogs handled by the handler.
        """
        t: float = (2 * math.pi) / len(self._collection)
        v: c4d.Vector = c4d.Vector(0, radius, 0)
        for dlg in self._collection:
            v *= c4d.utils.MatrixRotZ(t)
            dlg._position = c4d.Vector(int(position[0] + v.x), int(position[1] + v.y), 0)
            dlg.Open(c4d.DLG_TYPE_ASYNC_POPUPEDIT, xpos=int(dlg._position.x), ypos=int(dlg._position.y))
            self._collection[item][0] = True
        
        dlg.SetTimer(250) 
    
    def OnTimerTick(self, sender: "MenuContainer", msg: c4d.BaseContainer) -> None:
        """Called by the last dialog in #_collection with a stride of 250ms.

        We use this to jump over a "focus gap". When we have three dialogs with the focus state:

            [t, f, f]

        i.e., the first dialog is focused. When the user now switches the focus, because he/she
        opens the menu of dialog 2, then the next state is not:

            [f, t, f]

        but 
            [f, f, f]
        
        because we are here inside a message stream and for a brief moment no dialog is in focus,
        the stream will be:

            [t, f, f]
            [f, f, f]
            [f, t, f]

        But we still have to catch the event when the user clicks somewhere outside of the menu and
        with that de-focuses all elements. So we use this timer to check every 250ms if the state
        is [f, f, f] and then close all dialogs.

        Note that what I did here is quite error prone, as there is nothing which prevents this
        from happening (this is exaggerated there is not for 100ms no dialog in focus when 
        one switches focus, it more like 2-3 ms between such messages) :

            0.000ms: Timer Tick
            0.100ms: The user switches focus.
            0.200ms: Dialog 1 is defocused, all dialogs are now out of focus.
            0.250ms: Timer Tick, all dialogs are out of focus, the menu is closed.
            0.300ms: Cinema 4D tries to set Dialog 2 into focus (and possibly crashes because the 
                     dialog does not exist anymore).

        To avoid this, we would have to set the tick frequency to something like 100ms and then use
        three events.

            1st tick: Store the current focus state
            2nd tick: Establish that no elements are selected.
            3rd tick: Establish that STILL all elements are selected and then close the menu.

        This would ensure that always at least 100 ms have passed with no dialog in focus.
        """
        if not any([state[1] for state in self._collection.values()]):
            list(self._collection.keys())[0].Close() # Due to OnClose, closing one will close all.

    def OnFocusChange(self, sender: "MenuContainer", state: bool) -> None:
        """Called by #MenuContainer when it changes its focus state.
        """
        self._collection[sender][1] = state

    def OnClose(self, sender: "MenuContainer") -> None:
        """Called by #MenuContainer when it its closing.
        """
        self._collection[sender][0] = False
        for dlg, (isOpen, _) in self._collection.items():
            if isOpen:
                dlg.Close()

    def Add(self, item: "MenuContainer") -> None:
        """Adds a #MenuContainer to the managed dialogs of this radial menu.
        """
        if not isinstance(item, MenuContainer):
            raise TypeError(f"{item = }")
        if item in self._collection.keys():
            raise KeyError(f"{item = }")
        
        item._handler = self
        self._collection[item] = [False, False]

class MenuContainer(c4d.gui.GeDialog):
    """Realizes a dialog which renders a title onto its canvas and opens a popup menu when the 
    canvas is clicked.
    """
    def __init__(self, menu: dict) -> None:
        """Inits the dialog instance with a #menu dict.
        """
        def BuildMenu(menu: dict, title: str = "") -> c4d.BaseContainer:
            """Converts a dict menu representation into its BaseContainer form.

            The scheme of these dicts is of course not set in stone and there could be many more
            things we can do, this form assume that there is a CallCommand (and icon) for each item. 
            """
            bc: c4d.BaseContainer = c4d.BaseContainer()
            if title != "":
                bc.InsData(1, title)
            for key, value in menu.items():
                if isinstance(value, int):
                    bc.InsData(value, f"{key}&i{value}&")
                elif isinstance(value, dict):
                    sub: c4d.BaseContainer = BuildMenu(value, key)
                    bc.InsData(c4d.MENURESOURCE_SUBMENU, sub)
            return bc
        
        self._handler: RadialHandler = None
        self._title: str = menu.get("title", "None")
        self._items: c4d.BaseContainer = BuildMenu(menu.get("items", {}))
        self._position: c4d.Vector = c4d.Vector(0, 0, 0)

    def Command(self, id: int, msg: c4d.BaseContainer) -> bool:
        """Opens the menu when the dialog is clicked and closes all dialogs by closing this dialog
        when the user clicked an item.
        """
        res: int = c4d.gui.ShowPopupDialog(self, self._items, int(self._position.x), int(self._position.y))
        if res != 0:
            self.Close()
        return True
    
    def AskClose(self) -> bool:
        """Propagates the closing event of this dialog to the handler.
        """
        self._handler.OnClose(self)
        return False
    
    def CreateLayout(self) -> bool:
        """Adds the menu title to the dialog.
        """
        # Prepare the bitmap button container, we will draw the button without any bitmap, we are
        # only after having a button with a centred text over the whole horizontal width. We could
        # also use a GeUserArea instead to be more custom.
        bc: c4d.BaseContainer = c4d.BaseContainer()
        bc.SetInt32(c4d.BITMAPBUTTON_BACKCOLOR, c4d.COLOR_BG)
        bc.SetBool(c4d.BITMAPBUTTON_DISABLE_FADING, True)
        bc.SetString(c4d.BITMAPBUTTON_STRING, self._title)

        # Add the button.
        if not self.AddCustomGui(1000, c4d.CUSTOMGUI_BITMAPBUTTON, "", c4d.BFH_SCALE, 0, 0, bc):
            raise MemoryError("Could not allocate bitmap button.")
        
        return True

    def Message(self, msg: c4d.BaseContainer, result: c4d.BaseContainer) -> int:
        """Propagates the focus events of this dialog to the handler.
        """
        mid: int = msg.GetId()
        if mid == c4d.BFM_GOTFOCUS:
            self._handler.OnFocusChange(self, True)
        if mid == c4d.BFM_LOSTFOCUS:
            self._handler.OnFocusChange(self, False)
        return super().Message(msg, result)
    
    def Timer(self, msg: c4d.BaseContainer) -> None:
        """Sends timer ticks to the handler when the timer has been enabled for this dialog.
        """
        self._handler.OnTimerTick(self, msg)


if __name__ == "__main__":
    # Define five menus to be managed by the radial handler.
    collection: list[MenuContainer] = [
        MenuContainer({
            "title": "Objects",
            "items": {
                "Cube": c4d.Ocube,
                "Cone": c4d.Ocone,
                "Sphere": c4d.Osphere,
            }
        }),
        MenuContainer({
            "title": "Deformers",
            "items": {
                "Bend": c4d.Obend,
                "Twist": c4d.Otwist,
                "Shear": c4d.Oshear,
            }
        }),
        MenuContainer({
            "title": "Generators",
            "items": {
                "Extrude": c4d.Oextrude,
                "Lathe": c4d.Olathe,
                "Loft": c4d.Oloft,
                "Special": {
                    "SDS": c4d.Osds,
                    "Bool": c4d.Oboole
                }
            }
        }),
        MenuContainer({
            "title": "Splines",
            "items": {
                "Circle": c4d.Osplinecircle,
                "Rectangle": c4d.Osplinerectangle,
                "Flower": c4d.Osplineflower,
            }
        }),
        MenuContainer({
            "title": "Scene",
            "items": {
                "Light": c4d.Olight,
                "Camera": c4d.Ocamera,
                "Sky": c4d.Osky,
            }
        })
    ]

    # Add the menus to the handler and open it.
    handler: RadialHandler = RadialHandler()
    for item in collection:
        handler.Add(item)

    handler.Open(position=(300, 300), radius=100)

Hello @blkmsk,

Thank you for reaching out to us. There are multiple mistakes in your code, but instead of writing a lengthy answer, I decided to write a code example which we will ship with the next release of Cinema 4D.

Your main problem was not that you did not know how to get or set and port value, but that you did not understand the structure of a graph. And while it has been somewhat explained in our other examples, we lacked an example which dissected the topic in more detail. Which is why I wrote this example.

Cheers,
Ferdinand

#coding: utf-8
"""Demonstrates the inner structure of node graphs and how to find entities in them.

Run this script in the Script Manager on a document which contains at least one Redshift node 
material with at least one "Texture" node in the graph. The script will print out the URL of 
each texture node and print the GraphNode tree for each material in the document.

Topics:
    * The difference between node and asset IDs.
    * The inner structure of a graph.
    * Reading the value of a port (both for connected and unconnected ports).

Entities:
    * PrintGraphTree: Prints a given graph as a GraphNode tree to the console.
    * main: Runs the main example.
"""
__author__ = "Ferdinand Hoppe"
__copyright__ = "Copyright (C) 2023 MAXON Computer GmbH"
__date__ = "16/11/2023"
__license__ = "Apache-2.0 License"
__version__ = "2024.?.?"


import c4d
import maxon
import typing

doc: c4d.documents.BaseDocument # The active document.

def PrintGraphTree(graph: maxon.GraphModelRef) -> None:
    """Prints a given graph as a GraphNode tree to the console.

    This can be helpful to understand the structure of a graph. Note that this will print the true
    data of a graph, which will include all ports (most of them are usually hidden in the Node 
    Editor) and also hidden graph entities.
    """
    kindMap: dict[int, str] = {
        maxon.NODE_KIND.NODE: "NODE",
        maxon.NODE_KIND.INPORT: "INPORT",
        maxon.NODE_KIND.INPUTS: "INPUTS",
        maxon.NODE_KIND.NONE: "NONE",
        maxon.NODE_KIND.OUTPORT: "OUTPORT",
        maxon.NODE_KIND.OUTPUTS: "OUTPUTS",
    }
    if graph.IsNullValue():
        raise RuntimeError("Invalid graph.")
    
    def iterTree(node: maxon.GraphNode, 
                 depth: int = 0) -> typing.Iterator[tuple[int, maxon.GraphNode]]:
        """Yields all descendants of #node and their hexarchy depth, including #node itself.

        This is one way to iterate over a node graph. But when one does not require the hierarchy
        as we do here, one should use GraphNode.GetInnerNodes() as demonstrated in main() below.
        """
        yield (node, depth)
        for child in node.GetChildren():
            for item in iterTree(child, depth + 1):
                yield item
    
    root: maxon.GraphNode = graph.GetRoot()
    for node, depth in iterTree(root):
        print (f"{'  ' * depth} + '{node.GetId()}' [{kindMap.get(node.GetKind(), 'UNKNOWN KIND')}]"+
               ("" if not node.GetId().IsEmpty() else f"(Root Node)"))



def main():
    """Runs the main example.
    """
    # For each #material in the currently active document ...
    for material in doc.GetMaterials():
        # ... get its node material reference and step over all materials which do not have a 
        # Redshift graph or where the graph is malformed.
        nodeMaterial: c4d.NodeMaterial = material.GetNodeMaterialReference()
        if not nodeMaterial.HasSpace("com.redshift3d.redshift4c4d.class.nodespace"):
            continue

        graph: maxon.GraphModelRef = nodeMaterial.GetGraph(
            "com.redshift3d.redshift4c4d.class.nodespace")
        if graph.IsNullValue():
            raise RuntimeError("Found malformed empty graph associated with node space.")
        
        # Get the root of the graph, the node which contains all other nodes. Since we only want 
        # to read information here, we do not need a graph transaction. But for all write operations
        # we would have to start a transaction on #graph.
        root: maxon.GraphNode = graph.GetRoot()

        # Iterate over all nodes in the graph, i.e., unpack things like nodes nested in groups. 
        # With the mask argument we could also include ports in this iteration.
        for node in root.GetInnerNodes(mask=maxon.NODE_KIND.NODE, includeThis=False):
            
            # There is a difference between the asset ID of a node and its ID. The asset ID is
            # the identifier of the node template asset from which a node has been instantiated.
            # It is more or less the node type identifier. When we have three RS Texture nodes
            # in a graph they will all have the same asset ID. But their node ID on the other hand
            # will always be unique to a node.
            assetId: maxon.Id = node.GetValue("net.maxon.node.attribute.assetid")[0]
            nodeId: maxon.Id = node.GetId()

            # Step over everything that is not a Texture node, we could also check here for a node
            # id, in case we want to target a specific node instance.
            if assetId != maxon.Id("com.redshift3d.redshift4c4d.nodes.core.texturesampler"):
                continue

            # Now we got hold of a Texture node in a graph. To access a port value on this node,
            # for example the value of the Filename.Path port, we must get hold of the port entity. 

            # Get the Filename input port of the Texture node.
            filenameInPort: maxon.GraphNode = node.GetInputs().FindChild(
                "com.redshift3d.redshift4c4d.nodes.core.texturesampler.tex0")
            
            # But #filenameInPort is a port bundle - that is how ports are called which are composed
            # of multiple (static) child ports. The port has the data type "Filename" with which we 
            # cannot do much on its own. Just as in the node editor, we must use its 
            # nested child ports to get and set values, in this case the "path".
            pathPort: maxon.GraphNode = filenameInPort.FindChild("path")

            # Another way to get hold of the path port would be using a node path, where we define
            # an identifier which addresses the port node directly from the root of the graph.
            alsoPathPort: maxon.GraphNode = graph.GetNode(
                node.GetPath() + ">com.redshift3d.redshift4c4d.nodes.core.texturesampler.tex0\path")
            
            # The underlying information is here the nature of the type GraphNode. The word "node"
            # in it does not refer to a node in a graph but to a node in a tree. All entities in a
            # graph - nodes, ports, and things that are not obvious from the outside - are organized
            # in a tree of GraphNode instances. Each GraphNode instance has then a NODEKIND which
            # expresses the purpose of that node, examples for node kinds are:
            #
            #    * NODE_KIND.NODE   : A GraphNode that represents a tangible node in a graph. The
            #                          Nodes API calls this a 'true node'.
            #    * NODE_KIND.INPORT : A GraphNode that represents a input port in a graph.
            #    * NODE_KIND.OUTPORT: A GraphNode that represents a output port in a graph.
            #
            # For our example the GraphNode tree of a material graph could look like this:

            # + ""                                          // The root node of the graph, it is
            # |                                                is the container that holds all 
            # |                                                entities in the graph. It has the
            # |                                                empty ID as its ID.
            # |---+ "texturesampler@bbRMv5CAGpPtJFHs5n43CV" // An RS Texture node in it.
            # |   |---+ ">"                                 // A child node of the texture that 
            # |       |                                        holds all of its input ports, it has
            # |       |                                        a special NODE_KIND and is the 
            # |       |                                        underlying node of what we accessed 
            # |       |                                        with the .GetInputs() call above.
            # |       |---+ "...nodes.core.texturesampler"  // The Filename input port of a Texture 
            # |           |                                    node. It is a port bundle and 
            # |           |                                    therefore has child ports attached to
            # |           |                                    it. This node and all of its children
            # |           |                                    are of type NODE_KIND.INPORT.
            # |           |---+ "path"                      // The nested port for the Filename.Path.
            # |---+ "standardmaterial@FTf3YdB7AxEn1JKQL2$W" // An RS Standard Material node in the
            # |   |                                            graph. 
            # |   |---+ ">"                                 // Its input ports. 
            # |   |   |  ...
            # |   |
            # |   |---+ "<"                                 // Its output ports. 
            # |       |  ...
            # |
            # |---+ ...                                     // Another node in the graph.

            # On this entity we can now read and write values. In 2023 an earlier we would have used
            # Get/SetDefaultValue for this, in 2024 and onwards these methods have been deprecated
            # and we use GetValue now instead.
            url: str | None = pathPort.GetValue("effectivevalue")

            print (f"{pathPort}: {url}")
        
        # Print the GraphNode tree for the current #graph. 
        PrintGraphTree(graph)


if __name__ == "__main__":
    main()

Hey @justinleduc,

Thank you for reaching out to us. Your question is a bit contradictory, as you seem to mix up the terms volume and field as if they were interchangeable which then leads to other ambiguities.

• Volume: This is just an alias for voxel grid. This structure is by definition discrete, i.e., you can enumerate all values in that structure.
• Field: A field is just an alias for a function f(x, y, z) and it is therefore by definition continous/smooth. One cannot enumerate all values in it just as one cannot enumerate all rational numbers between 0 and 1.

So, when you talk about fields and show us a screenshot which contains a field object, and then ask for enumerating "all the lines" in that screenshot that is a bit ambiguous. Because if these vectors were generated by a field, all you could do is emulate that UI representation of that field, but a field does not have a finite set of values one could iterate over.

But I think field is just communicative noise here, and what you want to do, is sample a volume object which has been set to volume type vector. You can do that in Python but unlike in C++, we do not have GridIteratorInterface, so we must do some legwork ourselves.

Please share your code and scene examples in the future to make it easier for us to understand what you are doing and what you want to do. Find my answer below.

Cheers,
Ferdinand

Result:

Code:

"""Demonstrates how to iterate over all cells of a volume in Python.

Must be run as Script Manager script with a Volume Builder object selected which has been set to 
Volume Type: Vector. It will then print the vector values of all voxels. Since we do not have the
type GridIteratorInterface in Python, we must do some computations ourself here. We also lack 
fancier feature like voxel level folding in Python offered by GridIteratorInterface in C++.
"""

import c4d
import maxon
import itertools

op: c4d.BaseObject  # The active object.

def GetCenteredIndices(count: int) -> tuple[int, int]:
    """Yields indices for #count voxel cells centered on their index origin.

    So, 2 will yield [-1, 1], 3 will yield [-1, 0, 1], 4 will yield [-2, -1, 1, 2], 5 will yield 
    [-2, -1, 0, 1, 2], and so on.
    """
    if count % 2 == 0:
        half: int = int(count / 2)
        return [n for n in range(-half, 0)] + [n for n in range(1, half + 1)]
    else:
        half: int = int((count - 1) / 2)
        return [n for n in range(-half, 0)] + [0] + [n for n in range(1, half + 1)]


def main():
    """
    """
    # Validate the input.
    if not op or not op.IsInstanceOf(c4d.Ovolumebuilder):
        raise TypeError("op is not a c4d.Ovolumebuilder.")

    cache: c4d.modules.volume.VolumeObject | None = op.GetCache()
    hasVolumeCache: bool = cache and cache.IsInstanceOf(c4d.Ovolume)
    if not hasVolumeCache:
        raise RuntimeError("Object has no first level volume cache.")

    # Get the volume and ensure it has the grid type we/you expect it to have.
    volume: maxon.VolumeRef = cache.GetVolume()
    if volume.GetGridType() != c4d.GRIDTYPE_VECTOR32:
        raise RuntimeError("Object is not of matching vector32 grid type.")

    # Initialize a grid accessor so that we can access the volume data. In C++ we have
    # GridIteratorInterface which makes it much easier to iterate over all active cells
    # in a volume. Here we must get a bit creative ourselves.
    access: maxon.GridAccessorRef = maxon.GridAccessorInterface.Create(
        maxon.Vector32)
    access.Init(volume)

    # Get the transform of the volume. A volume, a voxel grid, is always world transform aligned. 
    # That means it cannot be rotated, but it can be scaled (expressing the cell size) and have an 
    # offset. In Python we also cannot use VolumeInterface.GetWorldBoundingBox() because while
    # the function has been wrapped, its return type has not (genius move I know :D). We use 
    # GetActiveVoxelDim() instead, which gives us the shape of the volume, e.g., (5*2*3) or 
    # (12*12*12) which in conjunction with the cell size then tells us the bounding box.
    transform: maxon.Matrix = volume.GetGridTransform()
    cellSize: maxon.Vector = transform.sqmat.GetLength()
    halfCellSize: c4d.Vector = c4d.Vector(cellSize.x * .5, cellSize.y * .5, cellSize.z * .5)
    shape: maxon.IntVector32 = volume.GetActiveVoxelDim()
    print(f"{transform = }\n{cellSize = }\n{shape = }\n")

    # Iterate over all cell indices in the volume. itertools.product is just a fancy way of doing
    # nested loops.
    for x, y, z in itertools.product(GetCenteredIndices(shape.x),
                                     GetCenteredIndices(shape.y),
                                     GetCenteredIndices(shape.z)):
        # Get the point in world coordinates for the cell index (x, y, z) and then its value.
        # In C++ we could just multiply our index by the volume #transform, here we must do some
        # legwork ourselves because most of the arithmetic types of the maxon API have not been 
        # wrapped in Python.

        # #p is the local lower boundary point coordinate of the cell index (x, y, z) and #q that 
        # point in global space which also has been shifted towards the cell origin.
        p: c4d.Vector = c4d.Vector(cellSize.x * x, cellSize.y * y, cellSize.z * z)
        q: c4d.Vector = c4d.Vector(cache.GetMg().off) + p + halfCellSize

        # Volumes are usually hollow, so most cells will hold the null value; we just step over them.
        value: maxon.Vector32 = access.GetValue(q)
        if value.IsNullValue():
            continue

        print(f"{q.x:>6}, {q.y:>6}, {q.z:>6}  =  {value}")


if __name__ == '__main__':
    main()

Here is also a section from some C++ code examples which I never got to ship which might be helpful here:

/// @brief Accesses the important metadata associated with a volume as for example its name, 
/// data type, transform, or bounding box. 
/// @param[in] volume The volume to access the metadata for.
static maxon::Result<void> GetVolumeMetadata(const maxon::Volume& volume)
{
  iferr_scope;

  // Get the purpose denoting label of the Pyro grid, e.g., "density", "color", or "velocity".
  const maxon::String gridName = volume.GetGridName();

  // Get the storage convention of the grid, e.g., FOG or SDF, and the data type which is being
  // stored in the grid. Currently, the only grid types that are being used are ::FLOAT and 
  // ::VECTOR32 regardless of the precision mode the simulation scene is in.
  const GRIDCLASS gridClass = volume.GetGridClass();
  const GRIDTYPE gridDataType = volume.GetGridType();

  // Get the matrix transforming from grid index space to world space. Due to volume grids always
  // being aligned with the standard basis orientation, the world axis orientation, this transform
  // will always express the standard orientation. The scale vector of the square matrix of this
  // transform expresses the size of a voxel in world space.
  const maxon::Matrix gridTransform = volume.GetGridTransform();

  // Get the shape of the whole grid, e.g., (5, 5, 5) for a grid with five cells on each axis.
  // Other than #GetWorldBoundingBox() and despite its name, this method will consider inactive
  // voxels in its return value. It will always return the shape of the whole grid.
  const maxon::IntVector32 gridShape = volume.GetActiveVoxelDim();

  // Get the index range of the active cells for the grid. E.g., a grid with the shape (5, 5, 5),
  // the origin (0, 0, 0), and all cells active would return [(-2, -2, -2), (2, 2, 2)]. But the
  // grid could also return [(-1, -1, -1), (1, 1, 1)] when no cells outside that range would be
  // active.
  const maxon::Range<Vector> indexRange = volume.GetWorldBoundingBox();

  // Get the cell size of a voxel in world space.
  const Vector cellSize = gridTransform.sqmat.GetScale();

  // Get the world space minimum and maximum of the active volume.
  const maxon::Range<Vector> boundingBox (gridTransform * indexRange.GetMin(),
                                          gridTransform * indexRange.GetMax());

  // Compute the size of the total and the active cells volume of the grid.
  const maxon::Vector totalVolumeSize (cellSize * Vector(gridShape));
  const maxon::Vector activeVolumeSize (boundingBox.GetDimension());

  // Log the metadata to the console of Cinema 4D.
  ApplicationOutput(
    "name: @, gridClass: @, gridDataType: @\n"
    "shape: @, indexRange: @\n"
    "gridTransform: @\n"
    "boundingBox: @, cellSize: @\n"
    "totalVolumeSize: @, activeVolumeSize: @", 
    gridName, gridClass, gridDataType, gridShape, indexRange, gridTransform, boundingBox, cellSize,
    totalVolumeSize, activeVolumeSize);

  return maxon::OK;
}
//! [GetVolumeMetadata]

//! [GetVolumeData]
/// @brief 
/// @tparam T 
/// @param volume 
/// @param result 
/// @return 
template<typename T>
maxon::Result<void> GetVolumeData(const maxon::Volume& volume, maxon::BaseArray<T>& result)
{
  iferr_scope;

  using GridIteratorType = maxon::GridIteratorRef<T, maxon::ITERATORTYPE::ON>;
  GridIteratorType iterator = GridIteratorType::Create() iferr_return;
  iterator.Init(volume) iferr_return;

  const maxon::Matrix gridTransform = volume.GetGridTransform();
  maxon::String msg;

  // Iterate over the first 100 cells yielded by the iterator and add each 10th value to the result.
  int i = 0; int j = 0;
  for (; iterator.IsNotAtEnd() && ++i < 100 && ++j; iterator.StepNext())
  {
    // Get the voxel index of the current cell and compute its world space position.
    const maxon::IntVector32 index = iterator.GetCoords();
    const Vector worldPosition = gridTransform * maxon::Vector64(index);
    // Get the depth in the voxel tree of the current cell; but Pyro volumes do not use any tiling.
    // #level will therefore always be of value #::LEAF and every active cell in the volume will be
    // visited by the iterator.
    const maxon::TREEVOXELLEVEL level = iterator.GetVoxelLevel();
    // Get the value stored in the current cell,
    const T value = iterator.GetValue();

    if (j % 10 == 0)
    {
      msg += FormatString("[@] @ (@): @\n", level, index, worldPosition, value);
      result.Append(value) iferr_return;
    }
  }

  // Log the collected data to the console of Cinema 4D.
  ApplicationOutput(msg);
  return maxon::OK;
}
//! [GetVolumeData]