Drawing a curve on surface is sometimes very wonky

Why is InterpcrvOnSrf creating these wonky red lines? Is there a better command for drawing a curve on surface?

I tried to add more points to guide the curve, but they just became more distorted.

COS-wonkiness.3dm (271.2 KB)

(Just for clarification, the result I expected from COS drawing is what you get if you place a straight line at those end points and pull them to the surface…)

Hello - ShortPath may get you what you need here if the input is two points.

Here’s a version I like better because of the preview
ShortPathEx.py (2.7 KB)

To use the Python script use RunPythonScript, or a macro:

_-RunPythonScript "Full path to py file inside double-quotes"

Also - CurveOnSurface | Food4Rhino



Thank you for the tips!

But two points:

  1. Oh my dear lord, why aren’t both of those things built into Rhino? :laughing:
  2. In what scenario is the result I posted from my file desired behavior?

EDIT: Oh, that poor 6+ year old user made plug-in does not work on polysurfaces (but then again, not many McNeel commands do either).