I need to create a surface to act as a cutting tool and I am using the left edge of the shape in the attached file, however I get invalid surface error when extruding it both ways.
If I select the lower part only so no horizontal lines I still get this error. invalid surface.3dm (47.2 KB)
I had by the way originally wished to create a surface heading outwards from the outlines you see, less the two lines added in heading north and south ! Couldnt see how to do that leaving that shape as a hole in the middle.
since realised to make the cut I didnt need that, just a ‘cutting sheet’.
As far as I know there isn’t such command, but I don’t work with Rhino on a daily basis since Rhino4, so what do I know. What I can suggest is to offset your curve outwards (this will most likely change your poly-curve. You could as well try to scale it 2d and project it on the (extruded) surface and trim accordingly.