Thank you @zipit for your comprehensive response, especially with the link to the coding guide. I guess it might be better to create the spline manually from the points which are connected by the edges without the usage of SendModellingCommand. It was good for prototyping functionality but as you mentioned, it is hard to debug. I appreciate you took the time (and I know it's a lot of convoluted code) to read through it. @r_gigante -> the work is currently on my side so you don't need to bother. I think I have enough information to do a second iteration and rewriting this from scratch.

Dear Python experts,

I am working on a Python Generator Plugin which creates Splines from Polygon Edges including some cleanup procedures. The problem I am facing is that the Generator works in a simple setup (e.g. it has a Voronoi Fracture or Clone under it) but when it comes in complex setups with more children it spins in an endless dirty loop. It really gets evil when Fields are involved in that setup. I tried everything including SetOptimizeCache(True) or checking dirty states of the children with a loop but nothing really helped here. Maybe it is because of all these modelling commands which probably make a scene dirty.

Could you provide me with some help? I know it is a generic question, I would like to be more specific but I don't know how. I would really appreciate your help here.

Here is the code of the entire plugin:

import os
import c4d
from c4d import plugins, utils, bitmaps
from c4d.utils import SplineHelp

class SplFromEdge(plugins.ObjectData):

    def Init(self, node):
        # Retrieves the BaseContainer Instance to set the default values
        #self.SetOptimizeCache(True)
        data = node.GetDataInstance()
        if data is None:
            return False
        
        data.SetBool(c4d.WELDSIMILAR, False)
        data.SetFloat(c4d.THRESHOLD, 0.01)
        data.SetInt32(c4d.O_SPLINEFROMEDGEMODE, c4d.O_SPLINEFROMEDGEMODE_TAG)
        data.SetBool(c4d.O_SPLINEFROMEDGEMODE_AUTOUPDATE , True)
        data.SetBool(c4d.CLOSE,True)
        data.SetBool(c4d.O_SPLINEFROMEDGEMODE_OPTIMIZE, True)
        return True

    #grey out the threshold in the UI
    def GetDEnabling(self, node, id, t_data, flags, itemdesc):
        data = node.GetDataInstance()
        weld = data.GetBool(c4d.WELDSIMILAR)
        if id[0].id == c4d.THRESHOLD:
            return weld

        # Retrieves the current interpolation
        inter = node[c4d.O_SPLINEFROMEDGEMODE]

        # Defines enable state for the selection
        if id[0].id == c4d.EDGESELECTION:
            return inter == c4d.O_SPLINEFROMEDGEMODE_TAG
        return True


    #iterator to go through the whole hierarchy
    def walk(self,op) :  
        if not op: return  
        elif op.GetDown() :  
            return op.GetDown()  
        while op.GetUp() and not op.GetNext():  
            op = op.GetUp()  
        return op.GetNext()  
    
    #has all modeling operators
    def ExecModelingCommand(self, doc,opCtrl, op, parent):
        if op is None:
            return

        data = opCtrl.GetDataInstance()
        threshold = data.GetReal(c4d.THRESHOLD)
        weld = data.GetBool(c4d.WELDSIMILAR)
        mode = data.GetInt32(c4d.O_SPLINEFROMEDGEMODE)
        selectionSet = data.GetString(c4d.EDGESELECTION)
        optimize = data.GetBool(c4d.O_SPLINEFROMEDGEMODE_OPTIMIZE)
        close = data.GetBool(c4d.CLOSE)
        
        splineHelper = SplineHelp()
        container = c4d.BaseContainer()
        
        childObject = op.GetClone(c4d.COPYFLAGS_NONE)
        # Creates a temporary document.
        tempDoc = c4d.documents.BaseDocument()
        # Insert the cloned object to the temporary document.
        tempDoc.InsertObject(childObject)
        
        tempParent = c4d.BaseObject(c4d.Onull)

        if childObject is None or (mode==c4d.O_SPLINEFROMEDGEMODE_TAG and selectionSet==""):
            return
 
        parent.SetMg(childObject.GetMg())

        c4d.StatusSetText("Creating Splines from Edges")
        c4d.StatusSetSpin()

        res = utils.SendModelingCommand(command=c4d.MCOMMAND_CURRENTSTATETOOBJECT,
                                    list=[childObject],
                                    mode=c4d.MODELINGCOMMANDMODE_ALL,
                                    bc=container,
                                    doc=tempDoc)

        if res is None:
            return
        
        editableObject = res[0]
        #select edges based on a selection tag
        def selectEdges(obj,tag):
            selection = tag.GetBaseSelect()
            polyselection = obj.GetEdgeS()
            selection.CopyTo(polyselection)

        #iterate through the new created polygon objects and look for the ones with an edge selection tag
        objectList = []   

        while editableObject:
            if editableObject.CheckType(c4d.Opolygon):
                if mode==c4d.O_SPLINEFROMEDGEMODE_TAG:
                    for i in editableObject.GetTags():
                        if i.GetName()==selectionSet and i.CheckType(c4d.Tedgeselection):
                            #select
                            selectEdges(editableObject,i)
                            #add to list                        
                            objectList.append(editableObject)
                elif mode==c4d.O_SPLINEFROMEDGEMODE_ALL:
                    utils.SendModelingCommand(c4d.MCOMMAND_SELECTALL, 
                                            list = [editableObject], 
                                            mode = c4d.MODELINGCOMMANDMODE_EDGESELECTION, 
                                            bc = c4d.BaseContainer())
                    objectList.append(editableObject)
            editableObject = self.walk(editableObject)
       
        if not objectList:
            c4d.StatusClear()
            return

        for i in objectList:
            i.InsertUnderLast(tempParent)

        spl = utils.SendModelingCommand(command=c4d.MCOMMAND_EDGE_TO_SPLINE,
                                            list=objectList,
                                            mode=c4d.MODELINGCOMMANDMODE_ALL,
                                            doc=objectList[0].GetDocument()) 

        c4d.StatusSetText("Optimizing Spline Objects")
        
        #Exploding Splines with multiple Segments which came from Edge to Spline
        splitList = []
        for i in objectList:
            child = i.GetDown()
            if child is not None:
                if child.CheckType(c4d.Ospline):

                    splineHelper.InitSpline(child)
                    if splineHelper.GetSegmentCount() !=1:
                        splitList.append(child)
 
        #Explode Splines using the Explode Command
        if splitList:
            expSplines = utils.SendModelingCommand(command=c4d.MCOMMAND_EXPLODESEGMENTS,
                                                                    list=splitList,
                                                                    mode=c4d.MODELINGCOMMANDMODE_ALL,
                                                                    flags=c4d.MODELINGCOMMANDFLAGS_NONE,
                                                                    doc=splitList[0].GetDocument()) 
        
        #Creating a Spline List which will be later added under a parent object
        splineList = []
        obj=objectList[0]
        while obj:
            if obj.CheckType(c4d.Ospline):
                splineHelper.InitSpline(obj)
                if splineHelper.GetSegmentCount() !=0:
                    #Add all spline objects to a dedicated spline list. Every object which is not in that list will be deleted
                    splineList.append(obj)
            obj = self.walk(obj)

        #optimize the spline for duplicate points
        optimizeBC = c4d.BaseContainer()
        optimizeBC[c4d.MDATA_OPTIMIZE_POINTS]= optimize
        optimizeBC[c4d.MDATA_OPTIMIZE_UNUSEDPOINTS]= True
        optimizeBC[c4d.MDATA_OPTIMIZE_TOLERANCE]= 0.01
        optimizedSplines = utils.SendModelingCommand(command=c4d.MCOMMAND_OPTIMIZE,
                                                                    list=splineList,
                                                                    bc= optimizeBC,
                                                                    mode=c4d.MODELINGCOMMANDMODE_ALL,
                                                                    flags=c4d.MODELINGCOMMANDFLAGS_NONE)
        
        #filter overlapping objects
        c4d.StatusSetText("Cleaning Up and Welding")

        positionList = []
        keyList = []
        noDuplicateSplineList = []
        for i in splineList:
            points = i.GetAllPoints()
            bary = c4d.Vector(0)
            #find the center of all points            
            for j in points:
                bary+=j
            bary = bary / len(points)
            # move the points by the amount represented by the new axis center              
            for index, point in enumerate(points) :  
                point = point - bary 
                i.SetPoint(index, point)  
            # notify about the points repositioning  
            i.Message(c4d.MSG_UPDATE)  
            # adjust the matrix offset component accordingly 
            currentMg = i.GetMg() 
            currentMg.off += bary
            # reposition the object in the space 
            i.SetMg(currentMg)
            #adjust object position
            polyParent = i.GetUp()
            offset = polyParent.GetMg().off
            #insert and adjust object position
            i.InsertUnderLast(tempParent)
            i[c4d.SPLINEOBJECT_CLOSED]=close
            currentMg = i.GetMg()
            currentMg.off += offset
            i.SetMg(currentMg)
            #remove overlapping splines if welding is active
            if weld:
                #check spline object position if it mateches a certain threshold
                overlapping = False
                if positionList:
                    for j in positionList:
                        p1 = i.GetMg().off
                        p2 = j.GetMg().off
                        distance = (p2-p1).GetLength()
                        
                        if distance <= threshold: 
                            overlapping = True  
                #check if it's overlapping and clear it
                key = int((i.GetRad().x+i.GetRad().y+i.GetRad().z)/threshold)
                if key in keyList and overlapping:
                    i.Remove()                    
                else:
                    keyList.append(key)
                    positionList.append(i)
                    noDuplicateSplineList.append(i)
            else:
                noDuplicateSplineList.append(i)
        c4d.StatusClear()
        
        #put everything under the parent null and return it
        for i in noDuplicateSplineList:
            i.InsertUnderLast(parent)

        return parent
    
    def GetVirtualObjects(self, op, hh):

        doc = op.GetDocument()
        data = op.GetDataInstance()       

        objInput = op.GetDown()
        
        if objInput is None:
            return None
        
        objRet = c4d.BaseObject(c4d.Onull)
        if doc is None or objRet is None:
            return None

        
        hierarchyClone = op.GetAndCheckHierarchyClone(hh, objInput, c4d.HIERARCHYCLONEFLAGS_ASPOLY, True)
        
        if hierarchyClone["dirty"] is False:
            return hierarchyClone["clone"]
            
        clone = hierarchyClone["clone"]
                
        if clone is None:
            return op.GetCache()
    
        self.ExecModelingCommand(doc, op, clone, objRet)
        return objRet

###############################################################################################################
# Plugin Registration
###############################################################################################################

PLUGIN_ID_GENERATOR = 954679

def RegisterObjectData(id, name, bmpPath, objData, desc, flags):
    bmp = bitmaps.BaseBitmap()
    bmp.InitWith(os.path.join(bmpPath, "res", "icon.tif"))
    plugins.RegisterObjectPlugin(id=id, str=name,
                                g=objData,
                                description=desc, icon=bmp,
                                info=flags)

if __name__ == "__main__":
    path, fn = os.path.split(__file__)

    RegisterObjectData(PLUGIN_ID_GENERATOR, "Spline from Edge", path, SplFromEdge, "osplinefromedge", c4d.OBJECT_GENERATOR | c4d.OBJECT_INPUT)

Amazing! Thank you Manuel! It works with multiple objects, Cloners etc. Without your help I would not make it

Hey Manuel,

I tried this method but I encountered another issue. The copy to another document does not work in a setup with a Mograph Effector. Therefore, I am inserting the object to the original document and try to remove the original. But that does not work. When I make ChamferGen editable, it creates the original Connect+Children objects as well as the editable Spline Object. I tried stuff like cloner.Remove() but that did not work. The setup is linked below.

I also have another question. How should I change the setup to support multiple children? (see image) I tried to insert multiple objects in the tempDoc via a loop but nothing really worked.

@m_magalhaes

Thank you for your help! It works. I really like the tip of the temporary document. Does it make sense to use c4d.documents.KillDocument(doc) after the process is complete to free up resources?

Hey Sebastian,
I wish you the best on your next challenges! Thank you so much for being such a help for the C4D Community!

Hey folks,

I could need your help on building a Python Generator version of the Chamfer Tool. It's based on the Py-Parametric tools build by Andreas back in days. There were very helpful for setting up the generator. But here comes the issue:
Using GetAndCheckHierarchyClone does not work well with the MCOMMAND_CURRENTSTATETOOBJECT (at least this is what I think). When I test the plugin and use a Cloner with Splines under a Connect Object, it only affects the first clone. When I make the Connect Object editable, it works on all objects. See images.
When I bypass the dirty check and add replace "clone" by "op" in line 63 in the "GetVirtualObjects" method, than it works, but very badly.

I would appreciate any kind of help

import os
import c4d
from c4d import plugins, utils, bitmaps

###############################################################################################################
#Based on the Py-Parametric Tools by Andreas Block
###############################################################################################################

class ModelingCommandGeneratorModifier(plugins.ObjectData):
    _toolId = -1
    _doSelection = False
    _selectId = -1

    def InitCommon(self, toolId, doSelection, selectId):
        self._toolId = toolId
        self._doSelection = doSelection
        self._selectId = selectId

    def ExecModelingCommand(self, doc, opCtrl, op, parent):
        if op is None:
            return
        
        splineObjects = []
        if op.GetDown().CheckType(c4d.Ospline) is False:
            splineObjects = utils.SendModelingCommand(command = c4d.MCOMMAND_CURRENTSTATETOOBJECT,
                                list = [op.GetDown()],
                                mode = c4d.MODELINGCOMMANDMODE_ALL,
                                bc = c4d.BaseContainer(),
                                doc = doc)
        else:
            splineObjects.append(op.GetDown())

        if not splineObjects:
            return
            
        if splineObjects[0].CheckType(c4d.Ospline) is True:
            res = utils.SendModelingCommand(command = self._toolId,
                                            list = splineObjects,
                                            mode = c4d.MODELINGCOMMANDMODE_ALL,
                                            bc = opCtrl.GetDataInstance(), # settings,
                                            doc = doc)
            if res is True:
                splineObjects[0].InsertUnderLast(parent)
        
    def GetVirtualObjects(self, op, hh):
        doc = op.GetDocument()
        objInput = op.GetDown()
        
        if objInput is None:
            return None
        
        objRet = c4d.BaseObject(c4d.Onull)
        if doc is None or objRet is None:
            return None
        hierarchyClone = op.GetAndCheckHierarchyClone(hh, objInput, c4d.HIERARCHYCLONEFLAGS_NONE, True)
        if hierarchyClone["dirty"] is False:
            return hierarchyClone["clone"]
        clone = hierarchyClone["clone"]
        if clone is None:
            return objRet
        
        #When I replace "clone" to "op" and bypass the dirty checks, than it works but very sluggish
        self.ExecModelingCommand(doc, op, clone, objRet)
        return objRet

class ChamferGen(ModelingCommandGeneratorModifier):
    def Init(self, op):
        ModelingCommandGeneratorModifier.InitCommon(self, c4d.ID_MODELING_SPLINE_CHAMFER_TOOL, False, -1)
        InitChamferDesc(self, op)
        return True

def InitChamferDesc(inst, op):
    inst.InitAttr(op, bool, [c4d.MDATA_SPLINE_CHAMFERFLAT])
    inst.InitAttr(op, float, [c4d.MDATA_SPLINE_CHAMFERRADIUS])
    
    op[c4d.MDATA_SPLINE_CHAMFERRADIUS] = 5.0


###############################################################################################################
# Plugin Registration
###############################################################################################################

PLUGIN_ID_GENERATOR = 9036026



def RegisterObjectData(id, name, bmpPath, objData, desc, flags):
    bmp = bitmaps.BaseBitmap()
    bmp.InitWith(os.path.join(bmpPath, "res", "icon.tif"))
    plugins.RegisterObjectPlugin(id=id, str=name,
                                g=objData,
                                description=desc, icon=bmp,
                                info=flags)

if __name__ == "__main__":
    path, fn = os.path.split(__file__)

    RegisterObjectData(PLUGIN_ID_GENERATOR, "ChamferGen", path, ChamferGen, "ochamfergen", c4d.OBJECT_GENERATOR | c4d.OBJECT_INPUT)

    print "ChamferGen 1.0 successfully initialized"

Thanks Maxime for clarifying. So we will wait for your fix

Hey, I run into the same issue on a Mac. I followed the instruction how to use c4dpy in VS Code but when I am pasting the path to c4dpy in the python interpreter settings, it does not accept it. No messages, nothing. I cannot select c4dpy as a python interpreter.

Greetings
Matthäus