ProjectToCplane refuses to project the curve in the attached to WorldXY. This is because it would produce a “bad object” - I assume one of the small segments is sufficiently vertical to produce a zero or near-zero length segment.
But, SetPt to Z0 does work - I get a “bad object” warning, but it produces a curve which I can simply explode/rejoin to produce a valid object. Funny, plain old Project to a planar surface at Z0 doesn’t even produce a bad object… But it’s not quite the same curve.
Perhaps I’m being utopian here, but I would like Rhino to try eliminating the vertical or near-vertical segments in order to produce a valid projection to CPlane. This would be practical in a lot of cases.
NoProject.3dm (92.9 KB)