Hi jonah,

Thanks a lot for the info. I have found the plugin from the RhinoLab. I tried the plugin with Rhino4SR2.
For example, draw a square curve then CreasseSplitting (with SplitAlongCreases=No), then ExtrudeCrv with the curve. but, it's a polysurface, not a single surface.
When extruding the curve, 'Cap=No' is making single surface, but 'Cap=Yes' is making polysurface and cannot turn on points. My objects are different from your image. What is my mistake?

Sorry all for the question about Rhino in the MoI Forum.

/momso