How to weld two points to the last selected point?

Gaal Dornik

Hello, currently this code welds two points in the middle, but i want it to weld to the last selected point, setting MDATA_WELD_TOPOINT to True doesn't help. How to solve this?

import c4d, sys


#
# M A I N
#
def main():
    doc = c4d.documents.GetActiveDocument()

    settings = c4d.BaseContainer()
    settings[c4d.MDATA_WELD_TOPOINT] = True
    
    result = c4d.utils.SendModelingCommand(
                    command=c4d.ID_MODELING_WELD_TOOL,
                    list=[op],
                    mode=c4d.MODELINGCOMMANDMODE_POINTSELECTION,
                    bc=settings,
                    doc=doc,
                    flags=c4d.MODELINGCOMMANDFLAGS_CREATEUNDO)

    if not result:
        raise RuntimeError(f"Modelling command failed for {op}.")

    # Inform Cinema 4D that the document has been modified.
    c4d.EventAdd()


# Execute main()
if __name__=='__main__':
    main()

i_mazlov

Hi @Gaal-Dornik ,

Sorry for the delayed answer.

The welding command was already comprehensively explained by Riccardo in this thread: ID_MODELING_WELD_TOO - Doesn't work [SOLVED].

In addition, the undo issue was discussed in the following thread: Problem on AddUndo and SendModellingCommand (Weld Tool)

As a compilation of both answers you can find the following code snippet (below) that welds currently selected points to the point with index pointIdx.

Cheers,
Ilia

import c4d

def main():
    doc = c4d.documents.GetActiveDocument()
    op = doc.GetActiveObject()

    pointIdx = 2  # FIXME: put here the index of the point you'd like to weld to'

    settings = c4d.BaseContainer()
    settings[c4d.MDATA_WELD_TOPOINT] = True
    settings[c4d.MDATA_WELD_POINTINDEX] = 2
    settings[c4d.MDATA_WELD_OBJECTINDEX] = op
    
    doc.StartUndo()
    doc.AddUndo(c4d.UNDOTYPE_CHANGE, op)
    
    result = c4d.utils.SendModelingCommand(
                    command=c4d.ID_MODELING_WELD_TOOL,
                    list=[op],
                    mode=c4d.MODELINGCOMMANDMODE_POINTSELECTION,
                    bc=settings,
                    doc=doc,)                
    doc.EndUndo()
    c4d.EventAdd()

if __name__=='__main__':
    main()

Gaal Dornik

@i_mazlov

The problem with this code - it doesn't always work correctly. Sometimes it's not taking into account selection order - welds to the first selected point for example. Look at this preview.

import c4d

def main():
    doc = c4d.documents.GetActiveDocument()
    op = doc.GetActiveObject()

    lastPoint = op.GetPointS().GetLastElement()

    settings = c4d.BaseContainer()
    settings[c4d.MDATA_WELD_TOPOINT] = True
    settings[c4d.MDATA_WELD_POINTINDEX] = lastPoint
    settings[c4d.MDATA_WELD_OBJECTINDEX] = op
    
    doc.StartUndo()
    doc.AddUndo(c4d.UNDOTYPE_CHANGE, op)
    
    result = c4d.utils.SendModelingCommand(
                    command=c4d.ID_MODELING_WELD_TOOL,
                    list=[op],
                    mode=c4d.MODELINGCOMMANDMODE_POINTSELECTION,
                    bc=settings,
                    doc=doc,)                
    doc.EndUndo()
    c4d.EventAdd()

if __name__=='__main__':
    main()

Gaal Dornik

Considering this thread it looks like getting points selection order is not trivial task for c4d api.

i_mazlov

Yes, you found the thread about point selection just right!