I think rs.IsPolyline does not work the way it should. The following code chunk will stop with an error if you select a point or anything but a polyline. I’d expect that it should finish gracefully with res=False.
import rhinoscriptsyntax as rs guid = rs.GetObject("select point") res = rs.IsPolyline(guid)
If you agree the fix would be simple: In curve.py, line 3165 the last argument should be converted from True to False and then read:
curve = rhutil.coercecurve(object_id, segment_index, False)
I’m running Rhino for Windows Version 6 SR17 (6.17.19235.15041, 23/08/2019)