Hey @freeze,

yes, clonerObj would be in your case the object which holds the generated MoGraph particle output in its cache. But generally speaking, you should not reach into caches. Sometimes it is necessary, but caches (be it generator or deform caches) are a dynamically generated part of the scene graph you usually should not interact with.

Just getting the matrices of the elements in the cache is fine (to print them or do something similar harmless). Establishing pointers into caches or relying on the fact that there is an established cache is not fine (note that my code checks for the cache actually being populated).

I still do not really understand what you want to do, but it strikes me as being on the 'you should really not do that' side. As I said in the beginning, MoGraph is a particle system and you are only supposed to interact with the abstract particle data.

I have the feeling you want to interact with the MoGraph particles as if they were tangible objects in the scene graph. This is simply not supported/intended.

Cheers,
Ferdinand

Good to hear!

That is perfect, thank you for being through and concise, lifesaver.

Hello @uogygiuol,

Welcome to the Maxon developers forum and its community, it is great to have you with us!

Getting Started

Before creating your next postings, we would recommend making yourself accustomed with our forum and support procedures. You did not do anything wrong, we point all new users to these rules.

Forum Overview: Provides a broad overview of the fundamental structure and rules of this forum, such as the purpose of the different sub-forums or the fact that we will ban users who engage in hate speech or harassment. Support Procedures: Provides a more in detail overview of how we provide technical support for APIs here. This topic will tell you how to ask good questions and limits of our technical support. Forum Features: Provides an overview of the technical features of this forum, such as Markdown markup or file uploads.

It is strongly recommended to read the first two topics carefully, especially the section Support Procedures: Asking Questions.

About your First Question

You can search for objects with c4d.documents.BaseDocument.SearchObject.

doc: c4d.documents.BaseDocument = c4d.documents.GetActiveDocument() target: c4d.BaseObject | None = doc.SearchObject("Eberhardt") if target is None: raise RuntimeError("Could not find target.")

Apart from the fact that names are a poor way to identify objects, you can also not find multiple objects with the same name in this manner. With release 2025 we added abstracted scene iteration.

doc: c4d.documents.BaseDocument = c4d.documents.GetActiveDocument() op: c4d.BaseObject = doc.GetFirstObject() # Walk the obejct tree and look for objects with a given name. for node in mxutils.IterateTree(op, True, True, True): if node.GetName() == "Eberhardt": pass # There is also abstract scene iteration now, here we look for any node named "Eberhardt" in #doc. for node in mxutils.RecurseGraph(doc, yieldBranches=True, yieldHierarchy=True): if node.GetName() == "Eberhardt": pass # Or for objects and tags named "Eberhardt". Check the docs on #RecurseGraph, there are a lot of # options for finetuning the scene traversal. for node in mxutils.RecurseGraph(doc, yieldBranches=True, yieldHierarchy=True, nodeFilter=[c4d.Obase, c4d.Tbase]): if node.GetName() == "Eberhardt": pass

Last but not least, what you are doing in your example code, recursion (at least unbound recursion) should be avoided, as this can quite easily lead to stack overflows. See this thread for how to do scene traversal manually.

Cheers,
Ferdinand

Hello,
Thanks for your complete answer.
I think I will not start in thread management, but opted for your last solution which will still go through an external image but in an automated way by a python script.
Thanks again.

Hi @derudo,

Welcome to the Maxon developers forum and its community, it is great to have you with us!

Getting Started

Before creating your next postings, we would recommend making yourself accustomed with our forum and support procedures. You did not do anything wrong, we point all new users to these rules.

Forum Overview: Provides a broad overview of the fundamental structure and rules of this forum, such as the purpose of the different sub-forums or the fact that we will ban users who engage in hate speech or harassment. Support Procedures: Provides a more in detail overview of how we provide technical support for APIs here. This topic will tell you how to ask good questions and limits of our technical support. Forum Features: Provides an overview of the technical features of this forum, such as Markdown markup or file uploads.

It is strongly recommended to read the first two topics carefully, especially the section Support Procedures: Asking Questions.

About your First Question

There's no single known "thing" we're aware of that could lead to such behavior. In other words, it can be lots of different "things" that caused the symptoms you're describing. Hence, without any further details everything I'm pointing out here is highly speculative.

I also don't think answering the question "What could have happened?" is by any means productive, so let's switch the point of view to "How one could diagnose it?".

Since you haven't posted any console output in your question, I assume you haven't checked that. This would actually be the first thing to check. Please refer to our Python Console Manual and searching on the forum.

Next, try to figure out if it's only UI that stopped appearing or your plugin isn't registered at all anymore. You can do this by checking (e.g. with some temporary print statements) if you plugin is actually functional.

On the screenshot you've posted the structure is kind of strange, but we're not sure if it's just a visualization matter of your software. Namely, the plugin.pyp file is expected to reside in the root of the plugin folder. Essentially, the following hierarchy level is not supposed to be there:
232c47cd-171e-4642-8c12-7661b51e6ce5-image.png
Please refer to the article Plugin Structure Manual: Directory Structure and double check your plugin in this regard.

If the points above don't lead to any result, try debugging it step-by-step. Namely, strip out everything except the essentials (like plugin registration) and continue adding things piece-by-piece until it starts failing. By the way, one can easily achieve this by using any version control system (e.g. git), as they typically provide a lossless way to manage your code (i.e. remove and add parts of code, without being worried to lose any of them). This approach could also have prevented your scenario in first place, when something stopped working and there're no clues about the change that has lead to it.

If this still doesn't help, you can share your plugin here (or send us via contact form, when confidential information is involved). However, I must warn you that our Support Procedures still fully apply, namely:

We cannot debug your code for you and instead provide answers to specific problems.

Cheers,
Ilia

Hey @BruceC,

Thank you for the added information, but I will still need that step by step bug report. Without it, I will not touch a debugger or a scene file. There are a plethora of reasons why this could go wrong. I am still very much in the dark at what you are looking exactly (e.g., are you using our Picture Viewer to view render results, or do you use your render engines one. What are your rendering and how, etc., pp.).

As I told you, applying a manual transform is not intended. It might be what you have to do as a work-around for older versions which we won't (hot)fix anymore, but there is no default answer here for you. But for all of that I first need a reliable bug/issue report which I can reproduce, and then other than you look at with a debug version of Cinema 4D. As I said, feel free to use your render engine, and please be precise in the reproduction steps. If you want to, you can also use our beta program bug tracker instead (since you are an MRD).

Cheers,
Ferdinand

Hey @Cankar001,

Good to hear that you found your solution! One minor thing - you should avoid ApplicationOutput in production code, as it leads to console spam which we want to avoid in Cinema 4D. Using it in test code is fine. See Debug and Output Functions for alternatives.

An even better way to do what you did in your code would be to use error handling. E.g., your code could look like this:

// Your original function, I turned this into a function using our error system, indicated by the // Result<T> return type. static maxon::Result<maxon::Float> GetCurrentUnitScale(const BaseDocument* const document) { // The error scope handler for this function, i.e., all error returns exit through this handler. iferr_scope; // When there is no document, we return an error. When printed, this will then print the error // message and the source code location, e.g., myfile.cpp:123. if (!document) return maxon::NullptrError(MAXON_SOURCE_LOCATION, "Invalid document pointer."_s); // Your code goes here. // ... return 1.0f; } // A function calling this function which does use error handling itself. static maxon::Result<void> Foo(const BaseDocument* const document) { iferr_scope; // Call the function and return, i.e., propagate the error upwards when there is one. const maxon::Float unitScale = GetCurrentUnitScale(document) iferr_return; // voids in the Result<T> return type are returned with maxon::OK. return maxon::OK; } // A function calling this function which does not use error handling itself, i.e., the error // must terminate here. static bool Bar(const BaseDocument* const document) { // Here we use a manual scope handler to terminate the error chain. You have often to do this in // Cinema API (e.g., ObjectData::GetVirtualObjects), as methods there are not error handled // opposed to the Maxon API. iferr_scope_handler { // Print a debug message with the passed in error #err and the name of this function. And // force a debugger to halt when some condition is met. WarningOutput("@ failed with error: @"_s, MAXON_FUNCTIONNAME, err); if (someErrorCondition) DebugStop(); return false; }; // Call the function (we still have to handle the error with an iferr_return), and then let it // terminate in our manual scope handler. const maxon::Float unitScale = GetCurrentUnitScale(document) iferr_return; return true; }

Cheers,
Ferdinand

Hi @mia-elisenberg,
Thanks for reaching out to us!

I must note that as per our Support Procedures we cannot debug your code. Hence, in your future postings I kindly ask you to try simplifying your code to a minimal viable example, which highlights your question.

Regarding your question, creating keyframes for nodes can be a little trickier comparing to the ordinary objects, but the general data accessing scheme stays the same. @Dunhou has thankfully posted the simplified example for your question, which already shows crucial pieces of how one would access the CTrack, CCurve and CKey for the node port. (@Dunhou I won't get tired showing our appreciation in playing an active role in our community! 😉 ). Namely, you're expected to use GetBaseListForNode to get the BaseList2D element that corresponds to the node you have. Additionally, NimbusBaseInterface.GetDescID can be used to get the DescID of the port. After you have this information, the process of interacting with animation data isn't any different. Your can check the animation examples in our repository: Cinema-4D-Python-API-Examples/scripts/04_3d_concepts/scene_elements
/animation.

The only thing I'd like to point out here is handling color data. Namely, CKey is designed to operate with float values, but Opacity channel works with color data. Hence, you need to create a separate CTrack for each color channel. You basically do this by pushing your DescID one level further to access the elements of your color data. Please find small example below (based on the code shared by @Dunhou):

descLevelsRGB: list[c4d.DescLevel] = [ c4d.DescLevel(c4d.COLOR_R, c4d.DTYPE_REAL, 0), c4d.DescLevel(c4d.COLOR_G, c4d.DTYPE_REAL, 0), c4d.DescLevel(c4d.COLOR_B, c4d.DTYPE_REAL, 0) ] opacityValue: list[float] = [0.55, 0.66, 0.77] # example data to store in the keyframe ctime: c4d.BaseTime = c4d.BaseTime(doc.GetTime().GetFrame(doc.GetFps()), doc.GetFps()) for opacityChannelDescLevel, opacityChannelValue in zip(descLevelsRGB, opacityValue): # Get opacity channel DescID and push it to access color channel channelDescID: c4d.DescID = nimbusRef.GetDescID(opacityPort.GetPath()) channelDescID.PushId(opacityChannelDescLevel) track: c4d.CTrack = c4d.CTrack(opacityPortBL2D, channelDescID) opacityPortBL2D.InsertTrackSorted(track) curve: c4d.CCurve = track.GetCurve() key = c4d.CKey() track.FillKey(doc, opacityPortBL2D, key) # this is optional key.SetValue(curve, opacityChannelValue) key.SetTime(curve, ctime) curve.InsertKey(key)

Cheers,
Ilia

@ferdinand
Thank you for the answer! The problem is solved after I try to find the child of the port according to your answer.

Hi Ferdinand, and thanks for all the fish! 🙂

No worries about the psuedo code, this is precisely what I needed to understand what I need to implement in order to store my data with the document. I am going to try to write this into my project, and will of course return soon if something happens that I can't figure out.

Again, many thanks!

Thank you so much! I couldn't ask for a more thorough response.

Dan

Hello @myosis,

Welcome to the Maxon developers forum and its community, it is great to have you with us!

Getting Started

Before creating your next postings, we would recommend making yourself accustomed with our forum and support procedures. You did not do anything wrong, we point all new users to these rules.

Forum Overview: Provides a broad overview of the fundamental structure and rules of this forum, such as the purpose of the different sub-forums or the fact that we will ban users who engage in hate speech or harassment. Support Procedures: Provides a more in detail overview of how we provide technical support for APIs here. This topic will tell you how to ask good questions and limits of our technical support. Forum Features: Provides an overview of the technical features of this forum, such as Markdown markup or file uploads.

It is strongly recommended to read the first two topics carefully, especially the section Support Procedures: Asking Questions.

About your First Question

All the methods you list simply do not exist (neither in C++ nor in Python), see c4d.utils.Neighbor for the type overview.

⚠ I therefore must assume that you are using an AI, like, for example, ChatGPT, which hallucinated these methods. Please note that we reserve the right to refuse support when confronted with undisclosed AI gibberish, especially for beginner content. Always state when you used an AI to generate code.

Something such as an edge does not exist concretely in our API and many other APIs, i.e., other than for points and polygons, there is no explicit data type for edges which would be stored. Edges are defined implicitly by CPolygon. To filter a selection for edges of a certain length, you would have to convert edge indices to polygon and point indices and then measure the distance between the relevant points.

Cheers,
Ferdinand

Result

074e2ada-a9ce-45b4-800a-acf7e060941a-image.png

Code """Deselects all edges in the edge selection of the active object whose edge length exceeds MAX_EDGE_LENGTH. Must be run as a Script Manager script with an editable polygon 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`. MAX_EDGE_LENGTH: float = 25.0 # The maximum length of an edge before to be considered too long. MAX_EDGE_LENGTH_SQUARED: float = MAX_EDGE_LENGTH ** 2 # The square of `MAX_EDGE_LENGTH`. def main() -> None: """Called by Cinema 4D when the script is being executed. """ if not op or not op.IsInstanceOf(c4d.Opolygon): raise ValueError("The selected object is not a polygon object.") # Get the edge selection of the object and turn it into a list of selected edges indices. Also, # get the points and polygons of the object. selection: c4d.BaseSelect = op.GetEdgeS() selectedEdges: list[int] = [i for i in range(op.GetEdgeCount()) if selection.IsSelected(i)] points: list[c4d.Vector] = op.GetAllPoints() polygons: list[c4d.CPolygon] = op.GetAllPolygons() def getPointByIndex(poly: c4d.CPolygon, index: int) -> c4d.Vector: """Returns the point of the polygon at the given index. CPolygon has no index access, so we fix that here. """ if index == 0: return points[poly.a] elif index == 1: return points[poly.b] elif index == 2: return points[poly.c] elif index == 3: return points[poly.d] # Iterate over the edges and find the one's that are longer than MAX_EDGE_LENGTH. An edge index # is defined as: # # "The edges are indexed by 4 * polygon + edge where polygon is the polygon index and edge is # the edge index between 0 and 3." # # So, we must revert that here, then measure the edge length, and collect all too long edges. tooLongEdges: list[int] = [] for edgeIndex in selectedEdges: polygonIndex: int = edgeIndex // 4 edgeInPolygonIndex: int = edgeIndex % 4 poly: c4d.CPolygon = polygons[polygonIndex] pointA: c4d.Vector = getPointByIndex(poly, edgeInPolygonIndex) pointB: c4d.Vector = getPointByIndex(poly, (edgeInPolygonIndex + 1) % 4) # Getting the length of a vector is quite expensive, so we compare the squared lengths. edgeLengthSq: float = (pointA - pointB).GetLengthSquared() if edgeLengthSq > MAX_EDGE_LENGTH_SQUARED: tooLongEdges.append(edgeIndex) # Print the indices of the edges that are too long. print("The following edges are too long:", tooLongEdges) # Deselect all edges in the object's edge selection that are too long. for edgeIndex in tooLongEdges: selection.Deselect(edgeIndex) # Push an update event to Cinema 4D to redraw the object. c4d.EventAdd() if __name__ == '__main__': main()

@ferdinand Thank you for your detailed answer.

I get it, thanks for your reply and keeping the idea.
If there are any workarounds or alternative solutions in the meantime, please let me know.
I look forward to any updates regarding this feature in the future.
Cheers~

@i_mazlov I get it, thanks for your reply.

@Dunhou @i_mazlov
Thanks a lot.😊 😊 😊

@ferdinand Wow, thanks a ton for that! Our workflow was working just fine without c4dpy, so I didn't get to check the forum again, but this is very nice.

Happy new year!

Hi @serco, there is multiple way to execute a script automatically when Cinema 4D is opened.

Use python_init.py, this force you to add your script into the temp folder. Bu it can be done for a particular instance of a Cinema 4D or it can also be applied to all Cinema 4D versions that use a given python version. Implement a Plugin and react to PluginMessage various event are sent to Python, and you can hook into them to execute your code. This require to have a Python plugin loaded by Cinema 4D. Depending of your needs there is c4dpy which act as a Python Interpreter, where you can pass directly your Python file as an argument. Then again depending of your need you may be able to start what you want to do next.

Cheers,
Maxime.

Thanks a lot for reporting this kind of issue !
This is going to be fixed in the next update of the doc.

Cheers,
Maxime.