How to Add Child Shaders to a Fusion Shader?

[HerrMay]

Hi guys, I noticed some odd behavior regarding shader creation with python scripts.

The situation is as follows. I use the Treeview example made by Niklas Rosenstein to display a material/shader tree. And I have a simple test script for creating a material and inserting some shaders into it.

When I create the material manually, the Treeview is showing the correct hierarchy of the material with all its shaders and possible sub-shaders. But when I create it via script the Treeview is showing the fusion shader without its sub-shaders.

It seems almost as cinema does'nt get informed correctly about the new material and its shaders that is. Am I missing something here?

Cheers,
Sebastian

edit ( @ferdinand ) : I change the title to better reflect the subjects in the thread.

TL;DR
The script to create the aforementioned material:

import c4d

def main():

    doc = c4d.documents.GetActiveDocument()
    doc.StartUndo()

    ao = c4d.BaseShader(c4d.Xambientocclusion)
    color = c4d.BaseShader(c4d.Xcolor)
    fresnel = c4d.BaseShader(c4d.Xfresnel)

    fusion = c4d.BaseShader(c4d.Xfusion)
    fusion[c4d.SLA_FUSION_USE_MASK] = True
    fusion[c4d.SLA_FUSION_BLEND_CHANNEL] = ao
    fusion[c4d.SLA_FUSION_MASK_CHANNEL] = color
    fusion[c4d.SLA_FUSION_BASE_CHANNEL] = fresnel
    fusion.InsertShader(ao)
    fusion.InsertShader(color)
    fusion.InsertShader(fresnel)

    mat = c4d.BaseMaterial(c4d.Mmaterial)
    mat[c4d.MATERIAL_COLOR_SHADER] = fusion
    mat.InsertShader(fusion)
    mat.Message(c4d.MSG_UPDATE)
    mat.Update(preview=True, rttm=True)

    doc.InsertMaterial(mat)
    doc.AddUndo(c4d.UNDOTYPE_NEW, mat)
    doc.EndUndo()
    c4d.EventAdd()

if __name__=='__main__':
    main()

The Treeview example code:

# Example of using the Cinema 4D Tree View GUI in Python.

import c4d
import os
import weakref

# Be sure to use a unique ID obtained from [URL-REMOVED]
PLUGIN_ID = 9912399
PLUGIN_NAME = "Python TreeView Example"
PLUGIN_HELP = "Show the current scene hierarchy in a tree."

# Bit for the Checkbox in the GUI. Kind of a bad practice to use this
# but reduces complexity for this example.
BIT_CHECKED = 256
# TreeView Column IDs.
ID_CHECKBOX = 1
ID_ICON = 2
ID_TREEVIEW = 3
ID_TREEVIEW_TYPE = 4
ID_TREEVIEW_CHANNEL = 5


def get_next(node):

    if isinstance(node, c4d.Material) and node.GetFirstShader():
        return node.GetFirstShader()

    if node.GetDown():
        return node.GetDown()
        
    while not node.GetNext() and node.GetUp():
        node = node.GetUp()
        
    return node.GetNext()


def iter_children(node):
    """Yields all descendants of ``node`` in a truly iterative fashion.

    The passed node itself is yielded as the first node and the node graph is
    being traversed in depth first fashion.

    This will not fail even on the most complex scenes due to truly
    hierarchical iteration. The lookup table to do this, is here solved with
    a dictionary which yields favorable look-up times in especially larger
    scenes but results in a more convoluted code. The look-up could
    also be solved with a list and then searching in the form ``if node in
    lookupTable`` in it, resulting in cleaner code but worse runtime metrics
    due to the difference in lookup times between list and dict collections.
    """
    if not node:
        return

    # The lookup dictionary and a terminal node which is required due to the
    # fact that this is truly iterative, and we otherwise would leak into the
    # ancestors and siblings of the input node. The terminal node could be
    # set to a different node, for example ``node.GetUp()`` to also include
    # siblings of the passed in node.
    visisted = {}
    terminator = node

    while node:
        # C4DAtom is not natively hashable, i.e., cannot be stored as a key
        # in a dict, so we have to hash them by their unique id.
        node_uuid = node.FindUniqueID(c4d.MAXON_CREATOR_ID)
        if not node_uuid:
            raise RuntimeError("Could not retrieve UUID for {}.".format(node))

        # Yield the node when it has not been encountered before.
        if not visisted.get(bytes(node_uuid)):
            yield node
            visisted[bytes(node_uuid)] = True

        # Attempt to get the first child of the node and hash it.
        child = node.GetDown()

        if child:
            child_uuid = child.FindUniqueID(c4d.MAXON_CREATOR_ID)
            if not child_uuid:
                raise RuntimeError("Could not retrieve UUID for {}.".format(child))

        # Walk the graph in a depth first fashion.
        if child and not visisted.get(bytes(child_uuid)):
            node = child

        elif node == terminator:
            break

        elif node.GetNext():
            node = node.GetNext()

        else:
            node = node.GetUp()


def iter_shader(shader):

    for shd in iter_children(shader):
        yield shd


def iter_baselist(node):

    while node:
        yield node
        node = node.GetNext()


class Hierarchy(c4d.gui.TreeViewFunctions):

    def __init__(self, dlg):
        # Avoid a cyclic reference.
        self._dlg = weakref.ref(dlg)

    
    def GetShader(self, shader):
        doc = c4d.documents.GetActiveDocument()
        mat = doc.GetFirstMaterial()
        return next(iter_shader(mat[shader]), None)


    def GetFirst(self, root, userdata):
        """
        Return the first element in the hierarchy. This can be any Python
        object. With Cinema 4D nodes, it is easy to implement, but it could
        as well be a Python integer which you can use as an index in a list.

        Returns:
        (any or None): The first element in the hierarchy or None.
        """

        doc = c4d.documents.GetActiveDocument()
        return doc.GetFirstMaterial()


    def GetDown(self, root, userdata, node):
        """
        Returns:
        (any or None): The child element going from *node* or None.
        """

        if isinstance(node, c4d.Material):
            return node.GetFirstShader()
        
        return node.GetDown()


    def GetNext(self, root, userdata, node):
        """
        Returns:
        (any or None): The next element going from *node* or None.
        """

        return node.GetNext()


    def GetPred(self, root, userdata, node):
        """
        Returns:
        (any or None): The previous element going from *node* or None.
        """

        return node.GetPred()


    def GetName(self, root, userdata, node):
        """
        Returns:
        (str): The name to display for *node*.
        """

        return node.GetName()


    def Open(self, root, userdata, node, opened):
        """
        Called when the user opens or closes the children of *obj* in
        the Tree View.
        """
        
        doc = c4d.documents.GetActiveDocument()
        doc.StartUndo()
        doc.AddUndo(c4d.UNDOTYPE_CHANGE_SELECTION, node)

        if opened:
            node.SetBit(c4d.BIT_OFOLD)
        else:
            node.DelBit(c4d.BIT_OFOLD)

        doc.EndUndo()
        c4d.EventAdd()


    def IsOpened(self, root, userdata, node):
        """
        Returns:
        (bool): True if *obj* is opened (expaneded), False if it is
            closed (collapsed).
        """

        return node.GetBit(c4d.BIT_OFOLD)


    def DeletePressed(self, root, userdata):
        """
        Called when the user right-click Deletes or presses the Delete key.
        Should delete all selected elements.
        """

        def delete_recursive(node):
            if node is None: 
                return
                
            if node.GetBit(c4d.BIT_ACTIVE) == True:
                doc.AddUndo(c4d.UNDOTYPE_DELETE, node)
                node.Remove()
                return

            for child in node.GetChildren():
                delete_recursive(child)

        doc = c4d.documents.GetActiveDocument()
        doc.StartUndo()

        for mat in doc.GetMaterials():
            delete_recursive(mat)

        doc.EndUndo()
        c4d.EventAdd()


    def Deselect(self, doc):

        for mat in iter_baselist(doc.GetFirstMaterial()):
            doc.AddUndo(c4d.UNDOTYPE_CHANGE_SMALL, mat)
            mat.DelBit(c4d.BIT_ACTIVE)
            for shader in iter_children(mat.GetFirstShader()):
                doc.AddUndo(c4d.UNDOTYPE_CHANGE_SMALL, shader)
                shader.DelBit(c4d.BIT_ACTIVE)


    def Select(self, root, userdata, node, mode):
        """
        Called when the user selects an element.
        """

        doc = c4d.documents.GetActiveDocument()
        doc.StartUndo()
        doc.AddUndo(c4d.UNDOTYPE_CHANGE_SMALL, node)

        if mode == c4d.SELECTION_NEW:
            self.Deselect(doc)
            node.SetBit(c4d.BIT_ACTIVE)

        elif mode == c4d.SELECTION_ADD:
            node.SetBit(c4d.BIT_ACTIVE)

        elif mode == c4d.SELECTION_SUB:
            node.DelBit(c4d.BIT_ACTIVE)

        doc.EndUndo()
        c4d.EventAdd()


    def IsSelected(self, root, userdata, node):
        """
        Returns:
        (bool): True if *obj* is selected, False if not.
        """

        return node.GetBit(c4d.BIT_ACTIVE)


    def DoubleClick(self, root, userdata, node, col, mouseinfo):
        """
        Called when the user double-clicks on an entry in the TreeView.

        Returns:
        (bool): True if the double-click was handled, False if the
            default action should kick in. The default action will invoke
            the rename procedure for the object, causing `SetName()` to be
            called.
        """

        if col == ID_TREEVIEW:
            return False
        else:
            return True


    def IsResizeColAllowed(self, root, userdata, lColID):
        if lColID > 2:
            return True
        return False


    def IsTristate(self, root, userdata):
        return False


    def GetDragType(self, root, userdata, node):
        """
        Returns:
        (int): The drag datatype.
        """

        return c4d.NOTOK


    # def DragStart(self, root, userdata, node):
    #     """
    #     Returns:
    #     (int): Bitmask specifying options for the drag, whether it is
    #         allowed, etc.
    #     """

    #     return c4d.TREEVIEW_DRAGSTART_ALLOW | c4d.TREEVIEW_DRAGSTART_SELECT


    def GetId(self, root, userdata, node):
        """
        Return a unique ID for the element in the TreeView.
        """

        return node.GetUniqueID()


    def SetName(self, root, userdata, node, name):
        """
        Called when the user renames the element. `DoubleClick()` must return
        False for this to work.
        """

        doc = c4d.documents.GetActiveDocument()
        doc.StartUndo()
        doc.AddUndo(c4d.UNDOTYPE_CHANGE_SMALL, node)
        node.SetName(name)
        doc.EndUndo()
        c4d.EventAdd()


    def DrawCell(self, root, userdata, node, col, drawinfo, bgColor):
        """
        Called for a cell with layout type `c4d.LV_USER` or `c4d.LV_USERTREE`
        to draw the contents of a cell.
        """

        if col == ID_ICON:
            icon = node.GetIcon()
            drawinfo["frame"].DrawBitmap(
                icon["bmp"], drawinfo["xpos"], drawinfo["ypos"],
                16, 16, icon["x"], icon["y"], icon["w"], icon["h"], c4d.BMP_ALLOWALPHA)

        if col == ID_TREEVIEW_TYPE:
            name = node.GetTypeName()
            geUserArea = drawinfo["frame"]
            w = geUserArea.DrawGetTextWidth(name)
            h = geUserArea.DrawGetFontHeight()
            xpos = drawinfo["xpos"]
            ypos = drawinfo["ypos"] + drawinfo["height"]
            drawinfo["frame"].DrawText(name, xpos, ypos - h * 1.1)

        if col == ID_TREEVIEW_CHANNEL:
            if isinstance(node, c4d.Material):
                return

            if node == self.GetShader(c4d.MATERIAL_COLOR_SHADER):
                name = "Color"

            elif node == self.GetShader(c4d.MATERIAL_LUMINANCE_SHADER):
                name = "Luminance"

            elif node == self.GetShader(c4d.MATERIAL_DIFFUSION_SHADER):
                name = "Diffusion"
            
            else:
                name = ""

            if name != "":
                geUserArea = drawinfo["frame"]
                w = geUserArea.DrawGetTextWidth(name)
                h = geUserArea.DrawGetFontHeight()
                xpos = drawinfo["xpos"]
                ypos = drawinfo["ypos"] + drawinfo["height"]
                drawinfo["frame"].DrawText(name, xpos, ypos - h * 1.1)


    def SetCheck(self, root, userdata, node, column, checked, msg):
        """
        Called when the user clicks on a checkbox for an object in a
        `c4d.LV_CHECKBOX` column.
        """

        if checked:
            node.SetBit(BIT_CHECKED)
        else:
            node.DelBit(BIT_CHECKED)

        def checked_collect(op):
            if op is None: 
                return
            elif isinstance(op, c4d.documents.BaseDocument):
                for obj in op.GetObjects():
                    for x in checked_collect(obj):
                        yield x
            else:
                if op.GetBit(BIT_CHECKED):
                    yield op
                for child in op.GetChildren():
                    for x in checked_collect(child):
                        yield x

        status = ', '.join(obj.GetName() for obj in checked_collect(node.GetDocument()))
        self._dlg().SetString(1001, "Checked: " + status)
        self._dlg()._treegui.Refresh()


    def IsChecked(self, root, userdata, node, column):
        """
        Returns:
        (int): Status of the checkbox in the specified *column* for *obj*.
        """

        val = node.GetBit(BIT_CHECKED)

        if val == True:
            return c4d.LV_CHECKBOX_CHECKED | c4d.LV_CHECKBOX_ENABLED
        else:
            return c4d.LV_CHECKBOX_ENABLED


    def HeaderClick(self, root, userdata, column, channel, is_double_click, mouseX, mouseY, ua):
        """
        Called when the TreeView header was clicked.

        Returns:
        (bool): True if the event was handled, False if not.
        """

        c4d.gui.MessageDialog("You clicked on the '%i' header." % (column))
        return True


    def AcceptDragObject(self, root, userdata, node, dragtype, dragobject):
        """
        Called when a drag & drop operation hovers over the TreeView to check
        if the drag can be accepted.

        Returns:
        (int, bool)
        """

        # if dragtype != c4d.DRAGTYPE_ATOMARRAY:
        #     return 0

        # return c4d.INSERT_BEFORE | c4d.INSERT_AFTER | c4d.INSERT_UNDER, True

        return 0


    def GenerateDragArray(self, root, userdata, node):
        """
        Return:
        (list of c4d.BaseList2D): Generate a list of objects that can be
            dragged from the TreeView for the `c4d.DRAGTYPE_ATOMARRAY` type.
        """

        if node.GetBit(c4d.BIT_ACTIVE):
            return [node, ]


    def InsertObject(self, root, userdata, node, dragtype, dragobject, insertmode, bCopy):
        """
        Called when a drag is dropped on the TreeView.
        """

        if dragtype != c4d.DRAGTYPE_ATOMARRAY:
            return # Shouldnt happen, we catched that in AcceptDragObject

        for op in dragobject:
            op.Remove()

            if insertmode == c4d.INSERT_BEFORE:
                op.InsertBefore(node)
            elif insertmode == c4d.INSERT_AFTER:
                op.InsertAfter(node)
            elif insertmode == c4d.INSERT_UNDER:
                op.InsertUnder(node)
        return


    def GetColumnWidth(self, root, userdata, node, col, area):
        """Measures the width of cells.

        Although this function is called #GetColumnWidth and has a #col, it is
        not only executed by column but by cell. So, when there is a column
        with items requiring the width 5, 10, and 15, then there is no need
        for evaluating all items. Each item can return its ideal width and
        Cinema 4D will then pick the largest value.

        Args:
            root (any): The root node of the tree view.
            userdata (any): The user data of the tree view.
            obj (any): The item for the current cell.
            col (int): The index of the column #obj is contained in.
            area (GeUserArea): An already initialized GeUserArea to measure
             the width of strings.
        
        Returns:
            TYPE: Description
        """
        # The default width of a column is 80 units.
        width = 80
        # Replace the width with the text width. area is a prepopulated
        # user area which has already setup all the font stuff, we can
        # measure right away.

        if col == ID_ICON:
            return 5

        if col == ID_TREEVIEW:
            return area.DrawGetTextWidth(node.GetName()) + 5
            
        if col in (ID_TREEVIEW_TYPE, ID_TREEVIEW_CHANNEL):
            return area.DrawGetTextWidth(node.GetTypeName()) + 5
            
        return width


    def IsMoveColAllowed(self, root, userdata, lColID):
        # The user is allowed to move all columns.
        # TREEVIEW_MOVE_COLUMN must be set in the container of AddCustomGui.
        return False


    def GetColors(self, root, userdata, node, pNormal, pSelected):
        """
        Retrieve colors for the TreeView elements.

        Returns:
        (int or c4d.Vector, int or c4d.Vector): The colors for the normal
            and selected state of the element.
        """

        usecolor = node[c4d.ID_BASEOBJECT_USECOLOR]

        if usecolor == c4d.ID_BASEOBJECT_USECOLOR_ALWAYS:
            pNormal = node[c4d.ID_BASEOBJECT_COLOR]

        return pNormal, pSelected


    # Context menu entry for "Hello World!"
    ID_HELLOWORLD = 355435345


    def CreateContextMenu(self, root, userdata, node, lColumn, bc):
        """
        User clicked with the right mouse button on an entry so
        we can here enhance the menu
        """

        bc.SetString(self.ID_HELLOWORLD, "Set Original Name")


    def ContextMenuCall(self, root, userdata, node, lColumn, lCommand):
        """
        The user executes an entry of the context menu.

        Returns:
        (bool): True if the event was handled, False if not.
        """

        if lCommand == self.ID_HELLOWORLD:
            doc = c4d.documents.GetActiveDocument()
            doc.StartUndo()
            doc.AddUndo(c4d.UNDOTYPE_CHANGE_SMALL, node)
            node.SetName(node.GetTypeName())
            doc.EndUndo()
            c4d.EventAdd()
            return True

        return False


    def SelectionChanged(self, root, userdata):
        """
        Called when the selected elements in the TreeView changed.
        """

        print("The selection changed")


    def Scrolled(self, root, userdata, h, v, x, y):
        """
        Called when the TreeView is scrolled.
        """

        self._dlg().SetString(1002, ("H: %i V: %i X: %i Y: %i" % (h, v, x, y)))


class TestDialog(c4d.gui.GeDialog):

    _treegui = None

    def CreateLayout(self):
        # Create the TreeView GUI.
        customgui = c4d.BaseContainer()
        customgui.SetBool(c4d.TREEVIEW_BORDER, True)
        customgui.SetBool(c4d.TREEVIEW_HAS_HEADER, True)
        customgui.SetBool(c4d.TREEVIEW_HIDE_LINES, False)
        customgui.SetBool(c4d.TREEVIEW_MOVE_COLUMN, True)
        customgui.SetBool(c4d.TREEVIEW_RESIZE_HEADER, True)
        customgui.SetBool(c4d.TREEVIEW_FIXED_LAYOUT, True)
        customgui.SetBool(c4d.TREEVIEW_ALTERNATE_BG, True)
        
        self._treegui = self.AddCustomGui(
        1000, c4d.CUSTOMGUI_TREEVIEW, "", c4d.BFH_SCALEFIT | c4d.BFV_SCALEFIT,
        300, 300, customgui)

        if not self._treegui:
            print("[ERROR]: Could not create TreeView")
            return False

        self.AddMultiLineEditText(1001, c4d.BFH_SCALEFIT | c4d.BFV_SCALE | c4d.BFV_BOTTOM, 0, 40)
        self.AddEditText(1002, c4d.BFH_SCALEFIT, 0, 25)
        return True


    def CoreMessage(self, id, msg):
        if id == c4d.EVMSG_CHANGE:
            # Update the treeview on each change in the document.
            self._treegui.Refresh()
        return True


    def InitValues(self):
        # Initialize the column layout for the TreeView.
        layout = c4d.BaseContainer()
        layout.SetLong(ID_CHECKBOX, c4d.LV_CHECKBOX)
        layout.SetLong(ID_ICON, c4d.LV_USER)
        layout.SetLong(ID_TREEVIEW, c4d.LV_TREE)
        layout.SetLong(ID_TREEVIEW_TYPE, c4d.LV_USER)
        layout.SetLong(ID_TREEVIEW_CHANNEL, c4d.LV_USER)
        self._treegui.SetLayout(5, layout)

        # Set the header titles.
        self._treegui.SetHeaderText(ID_CHECKBOX, "Check")
        self._treegui.SetHeaderText(ID_ICON, "Icon")
        self._treegui.SetHeaderText(ID_TREEVIEW, "Name")
        self._treegui.SetHeaderText(ID_TREEVIEW_TYPE, "Type")
        self._treegui.SetHeaderText(ID_TREEVIEW_CHANNEL, "Channel")
        self._treegui.Refresh()

        # Don't need to store the hierarchy, due to SetRoot()

        root = doc = c4d.documents.GetActiveDocument()
        data_model = Hierarchy(self)
        self._treegui.SetRoot(root, data_model, None)

        self.SetString(1002, "Scroll values")

        return True


class MenuCommand(c4d.plugins.CommandData):

    dialog = None

    def Execute(self, doc):
        """
        Just create the dialog when the user clicked on the entry
        in the plugins menu to open it
        """

        if self.dialog is None:
            self.dialog = TestDialog()

        return self.dialog.Open(
            c4d.DLG_TYPE_ASYNC, PLUGIN_ID, defaulth=600, defaultw=600)

    def RestoreLayout(self, sec_ref):
        """
        Same for this method. Just allocate it when the dialog is needed.
        """

        if self.dialog is None:
            self.dialog = TestDialog()

        return self.dialog.Restore(PLUGIN_ID, secret=sec_ref)


def main():

    # c4d.plugins.RegisterCommandPlugin(
    #     PLUGIN_ID, PLUGIN_NAME, 0, None, PLUGIN_HELP, MenuCommand())

    global dialog
    dialog = TestDialog()
    dialog.Open(c4d.DLG_TYPE_ASYNC, defaulth=600, defaultw=600)


if __name__ == "__main__":
  main()

Re: Shader created by script does not get recognized by Treeview

Forgot to provide a screenshot that shows the difference. So here it is. It is taken in R26 but it makes no difference to R20.

---

[URL-REMOVED] @maxon: This section contained a non-resolving link which has been removed.

[ferdinand]

Hello @herrmay,

thank you for reaching out to us. You said,

When I create the material manually, [...]. But when I create it via script, [...]

implying that both operations are equal, but they are not. You insert the shader dependencies of your fusion shader into its shader branch, but that is by convention incorrect. Most shaders carry their dependencies as direct children. So, this

fusion.InsertShader(ao)
fusion.InsertShader(color)
fusion.InsertShader(fresnel)

should be replaced with this:

ao.InsertUnderLast(fusion)
color.InsertUnderLast(fusion)
fresnel.InsertUnderLast(fusion)

which will then result in this when comparing your old with this new output

For 2023.0 I just added the Access and Structure section to the C++ BaseShader manual which discusses the topic in more detail.

The underyling cause for the treeview not finding these shaders in in the malformed fusion shader, is due to your iter_children method. It traverses only hierachical descendants but not branches. Since shaders are not guranteed all to behave like our native layer or fusion shader, it would be better to fix your shader traversal. Here is how it could look like:

import c4d

doc: c4d.documents.BaseDocument  # The active document

def TraverseShaders(node: c4d.BaseList2D) -> c4d.BaseShader:
    """Yields all shaders that are hierarchical or shader branch descendants of #node.

    Semi-iterative traversal is okay in this case, at least I did not bother with implementing it fully
    iteratively here.

    In case it is unclear, you can throw any kind of node at this, BaseObject, BaseMaterial, 
    BaseShader, etc., to discover shaders which a descendants of them.
    """
    if node is None:
        return

    while node:
        if isinstance(node, c4d.BaseShader):
            yield node

        # The shader branch traversal.
        for descendant in TraverseShaders(node.GetFirstShader()):
            yield descendant 

        # The hierarchical traversal.
        for descendant in TraverseShaders(node.GetDown()):
            yield descendant

        node = node.GetNext()
        
def main() -> None:
    """
    """
    material: c4d.BaseMaterial = doc.GetActiveMaterial()
    print (f"{material = }\n")
    for shader in TraverseShaders(material):
        print (shader)

if __name__ == '__main__':
    main()

For the malformed fusion shader it would spit out this here:

Cheers,
Ferdinand

[HerrMay]

Hi @ferdinand,

well that makes sense. Of course - stupid me! Thanks for seeing things I obviously don't.

I have a follow up question which is kind of related but more towards the Treeview not the material/shader question. Should I rather open a new topic for that question?

Thank you @ferdinand. You really are golden to this forum and community.

Cheers,
Sebastian

[ferdinand]

Hey @herrmay,

I am glad that this solved your problem. For a question about the tree view GUI, I would ask you to open a new topic, as this one is mostly about shader traversal and the makeup of the fusion shader.

Cheers,
Ferdinand

[HerrMay]

Hi @ferdinand,

alright, will do.
Thanks again for the immediate help.

Cheers
Sebastian

[HerrMay]

Hello @ferdinand,

when trying out your function to traverse shaders I noticed that for two materials in the scene it yields for the first material all the shaders of itself but also all the shaders of the second material. For second material it works like expected and yields only the shaders of itself.

After fiddling around a bit with some other code of you from this post I think I ended up with a function that is yielding all the shaders from a material iteratively.

Find the code below. Maybe this will help others.

Cheers,
Sebastian

def iter_shaders(node):
    """Credit belongs to Ferdinand from the Plugincafe. I added only the part with the material and First Shader checking.

Yields all descendants of ``node`` in a truly iterative fashion.

    The passed node itself is yielded as the first node and the node graph is
    being traversed in depth first fashion.

    This will not fail even on the most complex scenes due to truly
    hierarchical iteration. The lookup table to do this, is here solved with
    a dictionary which yields favorable look-up times in especially larger
    scenes but results in a more convoluted code. The look-up could
    also be solved with a list and then searching in the form ``if node in
    lookupTable`` in it, resulting in cleaner code but worse runtime metrics
    due to the difference in lookup times between list and dict collections.
    """
    if not node:
        return

    # The lookup dictionary and a terminal node which is required due to the
    # fact that this is truly iterative, and we otherwise would leak into the
    # ancestors and siblings of the input node. The terminal node could be
    # set to a different node, for example ``node.GetUp()`` to also include
    # siblings of the passed in node.
    visisted = {}
    terminator = node

    while node:

        if isinstance(node, c4d.Material) and not node.GetFirstShader():
           break
        
        if isinstance(node, c4d.Material) and node.GetFirstShader():
            node = node.GetFirstShader()
        
        # C4DAtom is not natively hashable, i.e., cannot be stored as a key
        # in a dict, so we have to hash them by their unique id.
        node_uuid = node.FindUniqueID(c4d.MAXON_CREATOR_ID)
        if not node_uuid:
            raise RuntimeError("Could not retrieve UUID for {}.".format(node))

        # Yield the node when it has not been encountered before.
        if not visisted.get(bytes(node_uuid)):
            yield node
            visisted[bytes(node_uuid)] = True

        # Attempt to get the first child of the node and hash it.
        child = node.GetDown()

        if child:
            child_uuid = child.FindUniqueID(c4d.MAXON_CREATOR_ID)
            if not child_uuid:
                raise RuntimeError("Could not retrieve UUID for {}.".format(child))

        # Walk the graph in a depth first fashion.
        if child and not visisted.get(bytes(child_uuid)):
            node = child

        elif node == terminator:
            break

        elif node.GetNext():
            node = node.GetNext()

        else:
            node = node.GetUp()