Silent fail on trim

Can anyone explain why I’m allowed to trim my magenta curve with the black surfaces, but not the black curves?


trim-curve-silent-fail.3dm (147.3 KB)

(Before I even submitted this, I discovered a 0.16 degree discrepency of the circle rotation on the Y axis, but the curves don’t trim the curves even after that’s fixed…)

Hello - the lines do not intersect the circle, so you need to make sure ‘ApparentIntersections’ = Yes, and make sure you’re in a view where that does the right thing.


Ah. I guess we’re back to this and this then.

When you haven’t used Rhino for a while, it’s so difficult to remember that it’s probably the only CAD software in the world where the user doesn’t have control over trims (unless they intricately know the hidden rules of the system).