CSec Command - use 2D Curves for Input?

Rather than drawing curves in the command (Start of Cross Section Line, End of Cross Section Line), is it possible to use an existing 2D Curve?

This is so that I could update a history-enabled CSec with the existing 2D curve, which I’m using downstream for a Network Surface. The end Csecs then define where the ‘boundary’ of the Network Surface is.

Hello - CSec is always a plane defined by the two points picked and the perp to the construction plane. Do I understand that you want to use potentially non planar ‘paths’, i.e. any curve, not a line?


The input curve could certainly still be a planar line i.e. the normal input for CSec. But something that could be an existing line in the Rhino Document, and picked rather than drawn.

Then subsequently updated with History

I see - for now, though not very convenient, it is possible to set something up likes this with History and a little finagling.

Edit the red lines:

JH_Sections.3dm (49.8 KB)



Hi Pascal,

Thank you so much for looking into this (and introducing me to the word finagling…)

Yeah I think you’ve got what I mean - attached a video just incase. Basically I can endlessly edit one way which is great, but not in the CSec direction. I get though that the good thing about the CSec input is that it’s kind of becomes an infinite line based on the points created.