Another example of a polycurve which ProjectToCPlane will not project. Attempting to ProjectToCplane in the top view.
NotProject.3dm (1.7 MB)
A similar curve with the same structure projects, as well as many other similar curves in the original file. In this example the problem are the short segments normal to the Cplane. But the other curve which works has seemingly identical segments.
I previously reported a similar problem. ProjectToCplane does not work - bug? But in this example the short, perpendicular segment ends on the Cplane instead of being centered about it. The work-around is to use SetPt.