Hi Ilia,

Thank you very much, I was not aware of that!

Cheers!

As I said, you will run into access violations when you instantiate your fields on the class instead of the Init function. And as I also said, in your concrete case it would probably even be fine if you would directly do it in the class scope. But I would advise against breaking this rule. There is nothing to optimize here, either return a new instance when this is only called once in a blue moon and you do not want to bother with initializing a field. Or define a field and initialize it up in NodeData::Init. And no, scene elements (NodeData) should not share data on their class. We have types in the Maxon API to deal with this when you really want some heavy data structure which shall be initialized exactly once, but that is total overkill in this case.

Cheers,
Ferdinand

Hello @ferdinand ! Thanks for answer it is very clear, i will use virtual resolution from now on 🙂

Hey Ferdinand,

Thank you for the quick response! Ah ok I see. Thank you for the provided information, I will have a look at it.
But I can also wait for the moment.

My work arround for now would be to simply set everything up / import the parameters and colors with color management set to 'Basic' and manually doing the conversion via 'Convert to OCIO' in the Project settings. Thats giving me the correct result.

But thanks again!

Cheers,
Ben

Hey,

Out of curiosity, I did some poking in Redshift, and what I forgot, is that you are in principle unable to escape the current shading context of a sample in Redshift. I.e., you cannot just say, "screw the current UV coordinate, please sample my texture 'there'" due to the closure thing which Redshift has going.

With the Standard Renderer, you can do the following, which is pretty close. I compute the v (i.e., view angle coordinate) as described above. Standard also does not give you directly light ray angles, but you can get the light contribution where I use the diffuse component of the light(s) as a faksimile: High diffuse = high angle of incident/light contribution.

82ee51e1-15a9-487b-8cb0-91eec633352e-image.png
Fig. I: A crude iridescence setup in Standard. test.png is your texture from above, I forgot to take the inverse of values as 1 - x.

view_angle.zip

In Redshift you cannot do the same light contribution hack, and I currently do not see how you could set the sampling coordinate of the texture in the first place. Maybe the Redshift pro's know more.

Cheers,
Ferdinand

@m_adam Thanks, I await your info.
Have a nice weekend

No worries, everything is fine, that is what we are here for, to clear up things. When you have questions I encourage you to open a new thread so that we can see what we can do. And this is also an open forum, so you can ask questions to the community if you want to. But unless pointed out specifically otherwise, we assume things to be support requests.

Cheers,
Ferdinand

Good to hear. When you want to know more about how to expose libraries, I would recommend reading the Python Libraries Manual, as there are quite a few differences to a vanilla CPython. The guide is a little bit dated, I haven't updated it yet to the pip support Maxime is adding, and I also did not yet cover there mxutils.LocalImportPath.

Cheers,
ferdinand

Dear development community,

just as a clarification, as I was not very clear about that above. We are working on a solution for the build system for the SDK (as I hinted at before in other postings). But for 2025 we will stay with this a bit cumbersome legacy build system solution for macOS.

Please excuse the inconvenience but there are a few more moving parts in the background than it is obvious from the outside (to fix this, we must move away from the project tool).

Cheers,
Ferdinand

Hey Kent,

it depends a bit on the context. Generally, yes, flags and parameters passed to a BaseBitmap are piped through to the underlying ImageRef. But as I hinted at with the TIF settings for BaseBitmap::Save, some stuff is also ignored.

For fundamental stuff like initializing a bitmap with a channel depth, color format, etc., I am not aware of cases where flags are being ignored. But as I wrote in my pseudocode example, the exact nature of the BaseBitmap::GetImageRef is also quite important.

My very high level advice would be, use the Maxon Image API directly for simple things like loading, color converting, or saving an image, but avoiding it for complex tasks like for example assembling a multi layer image or drawing (not possible at all in the public API apart from 'dumb' pixel by pixel drawing). The problem with this is that when you must have a BaseBitmap output. Because while you can get an ImageRef from a BaseBitmap instance, there is no 'sane' public way to construct a BaseBitmap from an ImageRef you can of course copy over the buffer manually (not so sane) and there is a private way to do this but has its pitfalls (but is possible to do with the public API).

As I said, I would invite you to reach out to us with some code and a concrete use case when you get stuck, I will then be able able to help you specifically.

Cheers,
Ferdinand

PS: We recently dropped the term 'classic API' in favour of 'Cinema API'. We also capitalize now 'Maxon API'. Just saying this for clarity.

Hello @qq475519905,

Thank you for reaching out to us. Your question is very ambiguous. But given your posting history, I assume this is a development question and not an end user question. I.e., you are a developer who struggles with setting up a plugin which is being loaded, and you are not a user struggling with installing someone else's plugin (the latter would be out of scope of support for the developer forum).

We have plenty of Python plugin examples on Github, for anything more concrete, we will need a more concrete question from you. Most importantly executable example code which highlights your problem. Please have a look at Support Procedures: How to Ask Questions.

Cheers,
Ferdinand

hej, now it works!
now even in the "plugins" folder under C:/.../MAXON/Maxon Cinema 4D ...

Hey @ops,

Thank you for reaching out to us. Please excuse the delayed reply. You must use the c4d.modules.volume.VolumeBuilder interface for what you want to do, specifically its GetInputObject method. You have to understand that a volume builder is not a singular object, but a virtual tree of objects, and most parameters are located on one of these child objects. Cinema 4D then only displays the parameters of the child objects inline in the GUI (i.e., description) of the Volume Builder object.

5b76e06e-da90-4205-9e68-3e0ca7d14e8f-image.png
Fig.I: The internal makeup of a Volume Builder object. The virtual hierarchy in form of Volume Filter is inaccessible both via the Object Manager and things like GeListNode.GetChildren(). Instead we must use the dedicate UI and API interface to access them.

Cheers,
Ferdinand

Code """Sets the new min and max values of a Volume Builder fog range object. Must be run as a Script Manager script with a Volume Builder object selected. """ import c4d doc: c4d.documents.BaseDocument # The currently active document. op: c4d.BaseObject | None # The primary selected object in `doc`. Can be `None`. #: The volume builder fog range object type. We currently do not expose a symbol for this. c4d.Ofograngemap = 1039862 def main() -> None: """Called by Cinema 4D when the script is being executed. """ if not isinstance(op, c4d.modules.volume.VolumeBuilder): raise ValueError("The selected object is not a Volume Builder.") # Iterate over the objects in the Volume Builder 'Objects' parameter list. for i in range(op.GetInputObjectCount()): node: c4d.BaseList2D | None = op.GetInputObject(i) # Can happen for folders and on failure, there is no good way to distinguish between the two. if node is None: continue # This is a fog range object, we could do here further checks to ensure it is the correct one. if node.GetType() == c4d.Ofograngemap: print(f"{node[c4d.ID_VOLUMEFILTER_SDF_REMAP_NEW_MIN] = }") print(f"{node[c4d.ID_VOLUMEFILTER_SDF_REMAP_NEW_MAX] = }") # Set new values. node[c4d.ID_VOLUMEFILTER_SDF_REMAP_NEW_MIN] = 0.5 node[c4d.ID_VOLUMEFILTER_SDF_REMAP_NEW_MAX] = 2.0 # Push an update event to Cinema 4D to refresh the user interface. c4d.EventAdd() if __name__ == '__main__': main()

Oh,

my bad, I did overlook that you flagged this as S26. Yes, mxutils is a 2024+ feature. I used it here to carry out type checks, e.g., that a document or bitmap are not null/none. The code will run without them, but it will fail more gracefully with these checks.

You could replace these calls with manual checks:

bmp: c4d.bitmaps.BaseBitmap = c4d.bitmaps.MultipassBitmap( int(rData[c4d.RDATA_XRES]), int(rData[c4d.RDATA_YRES]), c4d.COLORMODE_RGB)) if bmp is None: # or more precise: if not isinstance(bmp, c4d.bitmaps.BaseBitmap) ... raise MemoryError("Failed to allocate bitmap.")

Cheers,
Ferdinand

Thanks for looking into it @m_adam.

Maybe this is specific to Arnold, but there are shader parameters that are not linkable. It's a flag on the parameter. Typically, boolean and enum type parameters are not linkable, like the ones highlighted in the screenshot below. But could be any parameters really, depending on the shader code.

image.png

Wow @m_adam , thanks for that, I'll check this after work!

Hey everyone,

Just as an FYI: cinema::GvCopyBuffer is not a public type. Just saying this so that future C++ users do not run against a wall here. One might be able to wiggle through with a forward/dummy deceleration of GvCopyBuffer, but officially this is not supported in the public C++ API either. And we therefore cannot provide forum support for this in C++ either.

Cheers,
Ferdinand

And that's good to know about using GetMl() over Get Mg(), mainly for the performance reasons if I understood correctly.

Thank you so much, this was very helpful to learn.
All the best.

Thank you for the quick answer.
Unfortunately this approach was quite destructive for my workflow, so i found a workaround using materials and 3d gradients. For anyone who want to render z-depth in python from c4d scene, this may be the approach. There may be some tweaks considering color space.
It would be nice to get access to this kind of data inside cinema 4d's python without crazy workarounds.

import c4d from c4d import gui, plugins, storage import os PLUGIN_ID = 1234567 # Replace this ID with your unique plugin ID from Maxon def GetFilterTypeFromFilename(filename): ext = os.path.splitext(filename)[1].lower() if ext == '.bmp': return c4d.FILTER_BMP elif ext == '.jpg' or ext == '.jpeg': return c4d.FILTER_JPG elif ext == '.png': return c4d.FILTER_PNG elif ext == '.tif' or ext == '.tiff': return c4d.FILTER_TIF elif ext == '.exr': return c4d.FILTER_EXR else: return c4d.FILTER_PNG # Default to PNG if extension is unrecognized class RenderDialog(gui.GeDialog): DESTINATION_FILE = 1001 BROWSE_BUTTON = 1002 RENDER_BUTTON = 2000 def CreateLayout(self): self.SetTitle("External Render Plugin") # Add Destination File Field self.GroupBegin(id=0, flags=c4d.BFH_SCALEFIT, cols=2) self.AddStaticText(id=0, flags=c4d.BFH_LEFT, name="Destination File:") self.AddEditText(id=self.DESTINATION_FILE, flags=c4d.BFH_SCALEFIT) self.GroupEnd() # Add Browse Button self.AddButton(id=self.BROWSE_BUTTON, flags=c4d.BFH_LEFT, name="Browse") # Add Render Button self.AddButton(id=self.RENDER_BUTTON, flags=c4d.BFH_CENTER, name="Render") return True def Command(self, id, msg): if id == self.BROWSE_BUTTON: path = storage.SaveDialog(title="Select Destination File") if path: self.SetString(self.DESTINATION_FILE, path) return True elif id == self.RENDER_BUTTON: path = self.GetString(self.DESTINATION_FILE) if not path: gui.MessageDialog("Please specify a destination file.") return True # Get the active document doc = c4d.documents.GetActiveDocument() # Create a large sphere object sphere = c4d.BaseObject(c4d.Osphere) sphere[c4d.PRIM_SPHERE_RAD] = 10000000 # Set radius to 10,000,000 m doc.InsertObject(sphere) c4d.EventAdd() # Check if a material named "LuminanceMaterial" already exists material = doc.SearchMaterial("LuminanceMaterial") if not material: # Create new material and set its parameters material = c4d.BaseMaterial(c4d.Mmaterial) material.SetName("LuminanceMaterial") material[c4d.MATERIAL_USE_COLOR] = False material[c4d.MATERIAL_USE_REFLECTION] = False material[c4d.MATERIAL_USE_LUMINANCE] = True # Create gradient shader and set it as luminance gradient_shader = c4d.BaseShader(c4d.Xgradient) if gradient_shader: gradient_shader[c4d.SLA_GRADIENT_TYPE] = c4d.SLA_GRADIENT_TYPE_3D_LINEAR # 3D Linear Gradient gradient_shader[c4d.SLA_GRADIENT_SPACE] = c4d.SLA_GRADIENT_SPACE_WORLD # World space gradient_shader[c4d.SLA_GRADIENT_CYCLE] = False material[c4d.MATERIAL_LUMINANCE_SHADER] = gradient_shader material.InsertShader(gradient_shader) # Insert material into the document doc.InsertMaterial(material) # Update gradient start and end points for the current camera gradient_shader = material[c4d.MATERIAL_LUMINANCE_SHADER] if gradient_shader: camera = doc.GetActiveObject() if not camera or camera.GetType() != c4d.Ocamera: camera = doc.GetRenderBaseDraw().GetSceneCamera(doc) if not camera: camera = doc.GetRenderBaseDraw().GetEditorCamera() if camera: start_position = camera.GetMg().off focus_distance = camera[c4d.CAMERAOBJECT_TARGETDISTANCE] end_position = start_position + (camera.GetMg().v3 * focus_distance) # Use v3 for z-axis direction gradient_shader[c4d.SLA_GRADIENT_START] = start_position gradient_shader[c4d.SLA_GRADIENT_END] = end_position # Enable material override in render settings rd = doc.GetActiveRenderData() rd[c4d.RDATA_MATERIAL_OVERRIDE] = True rd[c4d.RDATA_MATERIAL_OVERRIDE_LINK] = material # Set render settings rdata = rd.GetDataInstance().GetClone(c4d.COPYFLAGS_NONE) rdata[c4d.RDATA_PATH] = path rdata[c4d.RDATA_RENDERENGINE] = c4d.RDATA_RENDERENGINE_STANDARD # Create a bitmap to render into width = int(rdata[c4d.RDATA_XRES]) height = int(rdata[c4d.RDATA_YRES]) bmp = c4d.bitmaps.BaseBitmap() result = bmp.Init(width, height) if result != c4d.IMAGERESULT_OK: gui.MessageDialog("Failed to initialize bitmap.") return True # Trigger render render_result = c4d.documents.RenderDocument( doc, # Document to render rdata, # Render settings bmp, # Bitmap to render into c4d.RENDERFLAGS_EXTERNAL | c4d.RENDERFLAGS_DONTANIMATE # Flags ) if render_result != c4d.RENDERRESULT_OK: gui.MessageDialog("Render failed.") else: # Determine the appropriate file format filter filter_type = GetFilterTypeFromFilename(path) # Save the rendered image save_result = bmp.Save(path, filter_type, c4d.BaseContainer()) if save_result != c4d.IMAGERESULT_OK: gui.MessageDialog("Failed to save image.") else: gui.MessageDialog("Render completed and saved.") # Turn off material override after rendering rd[c4d.RDATA_MATERIAL_OVERRIDE] = False rd[c4d.RDATA_MATERIAL_OVERRIDE_LINK] = None # Delete the large sphere after rendering sphere.Remove() c4d.EventAdd() # Delete the material after rendering if material: material.Remove() c4d.EventAdd() # Refresh the document c4d.EventAdd() return True return False class ExternalRenderPlugin(plugins.CommandData): def __init__(self): self.dlg = None def Execute(self, doc): if not self.dlg: self.dlg = RenderDialog() self.dlg.Open(c4d.DLG_TYPE_ASYNC, defaultw=400, defaulth=100) return True if __name__ == "__main__": plugins.RegisterCommandPlugin( id=PLUGIN_ID, str="External Render Plugin", info=0, icon=None, help="Render current frame to a specified file", dat=ExternalRenderPlugin() )