@ferdinand Thank you for letting me know that switching between modes is irreversible! My initial thought was that when I generate an empty object in edit mode, if I undo the action, I could return to edit mode. Thanks again for your explanation

@ferdinand My English isn't very good, sorry about that. What I mean is that when I am in edit mode and select points/edges/polygons, create a null object, and then switch back to object mode, if I want to undo, it would be more 'user-friendly' if I could return to the previous edit mode instead of object mode
It's good to know that calling doc.SetMode(c4d.Mmodel) is non-undoable; I struggled with this for a while

@ferdinand Thank you for letting me know that switching between modes is irreversible! My initial thought was that when I generate an empty object in edit mode, if I undo the action, I could return to edit mode. Thanks again for your explanation

Hello all, my script needs to work in point, edge, and polygon modes (edit modes). At the end of the script, I will switch it back to model mode, but I'm not sure how to undo the mode switching. When I run the code in point mode, I can't return to point mode when undoing

import c4d

def main():
    sel = doc.GetActiveObjects(c4d.GETACTIVEOBJECTFLAGS_CHILDREN)
    if not sel or not doc.IsEditMode(): return # edit mode

    doc.StartUndo()
    for obj in sel:
        doc.SetSelection(obj, c4d.SELECTION_SUB)
        joint = c4d.BaseObject(c4d.Ojoint)
        doc.AddUndo( c4d.UNDOTYPE_NEWOBJ, joint)
        doc.InsertObject(joint, None, obj, True)
        doc.SetSelection(joint, c4d.SELECTION_ADD)
        ...

    doc.SetMode(c4d.Mmodel) # set model mode
    doc.EndUndo()
    c4d.EventAdd()

if __name__ == '__main__':
    main()

@ferdinand Thank you !

I hope to do something by clicking the update button on the Python node. I’m not sure if this is possible

Thank you @m_adam It seems that the best approach is to manually create a null object and calculate its correct rotation matrix through certain methods to achieve the same effect. Once again, thank you for your code; it has been very useful to me!

Hello everyone, when creating a splineIK tag, I dynamically call c4d.CallButton to create an IkHandle. At this point, an empty object is generated. I am now able to correctly retrieve it, but I can't add it to the undo queue. Since c4d.CallButton has no return value, I retrieve the empty object from the current scene each time I create an IkHandle. I'm not sure if there's a more proper way to do this

import c4d

def createJoints(jointCount):
    jntList = []
    for i in range(jointCount):
        jnt = c4d.BaseObject(c4d.Ojoint)
        jnt.SetName('splineIK_{}'.format(i))
        doc.InsertObject(jnt)
        doc.AddUndo(c4d.UNDOTYPE_NEW, jnt)
        jntList.append(jnt)
        if i > 0:
            jnt.InsertUnder(jntList[i-1])
    return jntList

def getAllNulls():
    return [obj for obj in doc.GetObjects() if obj.GetType() == c4d.Onull]

def addSplineTag(startJnt, endJnt, spline):
    tag = c4d.BaseTag(1019862)
    doc.AddUndo(c4d.UNDOTYPE_NEW, tag)
    startJnt.InsertTag(tag)
    tag[c4d.ID_CA_IKSPLINE_TAG_TYPE] = 2
    tag[c4d.ID_CA_IKSPLINE_TAG_TWIST_TYPE] = 1
    tag[c4d.ID_CA_IKSPLINE_TAG_SPLINE] = spline
    tag[c4d.ID_CA_IKSPLINE_TAG_END] = endJnt
    
    splineIkHandles = []
    for i in range(spline.GetPointCount()):
        c4d.CallButton(tag, c4d.ID_CA_IKSPLINE_HANDLE_ADD)
        c4d.CallButton(tag, c4d.ID_CA_IKSPLINE_HANDLE_CREATE)
        
        null = getAllNulls()[0]
        doc.AddUndo(c4d.UNDOTYPE_NEW, null) # add undo
        splineIkHandles.append(null)
        
    return splineIkHandles

def createSplineIK(jointCount=10):
    sel = doc.GetSelection()
    if not sel: return
    spline = sel[0] if sel[0].CheckType(c4d.Ospline) else None
    if spline is None: return

    doc.StartUndo()
    # ---------------------------------
    jnts = createJoints(jointCount)
    splineIkHandles = addSplineTag(jnts[0], jnts[-1], spline)
    for i in splineIkHandles:
        print(i.GetName())
    # ---------------------------------
    doc.EndUndo()
    c4d.EventAdd()

if __name__ == '__main__':
    createSplineIK(jointCount=10)

Thank u @i_mazlov
I appreciate you pointing me in the right direction. I will try to understand the workings behind the posemorph tag!

Hello everyone, I seem to have found a solution. You just need to go to the Falloff option in Morph and add a default parameter

 data = c4d.FieldList()
morph[c4d.FIELDS] = data

This way, the PoseMorph tag becomes effective. I still don't understand why this is necessary, as I can't find any python related content about the Morph deformer:(

test file

test.c4d