Snap a Profile Curve to a Surface Edge - Aligned?

I think I’ve seen this before, but I can’t find it - I want to attach an existing profile curve to a surface edge. How can I simply pick a profile, and align the profile to the angle of the surface? (rotate, perpendicular, tangent etc).

I often use Sweep1 profile curves to edges, like on car body parts, which can have very arbitrary angles. The profiles may lay elsewhere, in any orientation. So I would like to just pick an existing curve and have it aligned to the surface edges.

Is there any such a command in native Rhino or did I see it in a plug-in…

Dirty trick - too slow
My home made dirty trick - which is way too complex and time consuming - is to build a “frame” at both the profile curve and the surface edge with straight aligned lines
(perp etc), and then use Orient3Pt on the “frames”.

But, there must be a quicker and dirtier trick, no? See pictures :

Fig. 1: I want to do this (pick from A and place at B, aligned to the surface edge :

Fig. 2: My very complex method to align the profile (the yellow selected lines makes Orient3Pt useful here ) :

Hopefully there’s a better & quicker way.

// Rolf

Hi Rolf - 'OrientCrvToEdge’


OrientCrvToEdge to orient the curve perpendicular to the surface edge.

You may need to also rotate the curve after orienting it using Rotate3D

Turn SmartTrack on if it is not on. Also End OSnap should be on.
Start Rotate3D
Select the profile curve.
Pick the end of the curve at the surface edge as first point of axis to rotate about.
Move cursor in the direction tangent to the curve and a line should appear. That line will be a SmartTrack tangent to the end of the curve. Click to set the second point of the axis. Rotate curve as desired.

OK, there we go @pascal, I think it was was your video I had seen. Thank you.

@davidcockey, very useful hints,. Thank you, all these hints did the trick for me. :slight_smile: Thank you.

// Rolf