PERP Snap in CPlane

[Zarrtosht]

Hi!

I have a set of plane surfaces and a line above them, see below.

I want to draw a line from the line above the surfaces to one of the surface edges by using perpendicular osnap in my current CPlane. Is this possible in a simple manner?

This is what happens now:

Thanks!

[Zarrtosht]

question.3dm (492.0 KB)

[djnelson75]

A couple options to try, that I think should accomplish what you are after evoke Elevator mode.

Accurate drawing | Rhino 3-D modeling

or in the line options pick “perp”.

[Zarrtosht]

Thank you!

A follow-up:
How to do the same with dimension aligned?