Here's my prototype, if you are interested in my goal Right now, everything works as expected, but only with these lines of code. profile = GetCloneSpline(profile_orig) path = GetCloneSpline(path_orig) I'm happy with the current result. So, I'd love to get some additional advice on correctness and optimization. I think your previous answer was comprehensive enough, so I'll try to integrate some of it. But I'd also be very grateful if you could take a look at my plugin and perhaps give me some more specific optimization tips. If that's not too much trouble, of course! @ferdinand @ThomasB Anyway, thanks for your replies and advices!

Hi @Tpaxep, 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: How to Ask Questions. About your First Question The tool has indeed been updated, but the docs were not. Here is how to call it. Note that you have to pass a polygon index, this is mandatory and it needs to be adjacent to one of the vertex to indicate a direction of the ring selection. Here is your script adapted, to be run on a sphere that was made editable. import c4d from c4d import utils def select_ring_edge(obj, v1Id, v2Id, polyId): bc = c4d.BaseContainer() bc.SetData(c4d.MDATA_RING_SEL_STOP_AT_SELECTIONS, False) bc.SetData(c4d.MDATA_RING_SEL_STOP_AT_NON_QUADS, False) bc.SetData(c4d.MDATA_RING_SEL_STOP_AT_POLES, True) bc.SetData(c4d.MDATA_RING_BOTH_SIDES, False) bc.SetData(c4d.MDATA_RING_SWAP_SIDES, False) bc.SetData(c4d.MDATA_RING_FIRST_VERTEX, v1Id) bc.SetData(c4d.MDATA_RING_SECOND_VERTEX, v2Id) bc.SetData(c4d.MDATA_RING_POLYGON_INDEX, polyId) bc.SetData(c4d.MDATA_RING_SELECTION, c4d.SELECTION_NEW) result = c4d.utils.SendModelingCommand( command=c4d.ID_MODELING_RING_TOOL, list=[obj], mode=c4d.MODELINGCOMMANDMODE_EDGESELECTION, bc=bc, doc=c4d.documents.GetActiveDocument(), flags=c4d.MODELINGCOMMANDFLAGS_NONE ) c4d.EventAdd() return result def main(): doc = c4d.documents.GetActiveDocument() obj = doc.GetActiveObject() if obj is None: c4d.gui.MessageDialog("select obj.") return firstVertex = 346 secondVertex = 347 polygonIndex = 312 result = select_ring_edge(obj, firstVertex, secondVertex, polygonIndex) if result: print("DONE") else: print("ERROR") if __name__ == '__main__': main() Note that the same settings also apply for the ID_MODELING_LOOP_TOOL, just modify RING by LOOP in the constant so MDATA_RING_SEL_STOP_AT_SELECTIONS become MDATA_LOOP_SEL_STOP_AT_SELECTIONS. Cheers, Maxime.