Moving a trimmed edge of a surface


Please see attached snippet:

I’d like to ‘bend’ down this highlighted edge to meet the edge of the rectangle without moving the near edge with it.
When I move the control points I also take the near edge down with it.

If I use cageedit and raise the number of U & V points to a level that allows detailed manipulation
( around 40 each ) Rhino stalls and/or crashes.

Is there another way?

Thank you,


Hi @dcooke491
A little hard to tell without the actual file, but you could probably split the “offending” area from the main surface and either a) manipulate the split off part or b) build a new surface that fits with both the rectangle and the “main” surface.
HTH, Jakob

Thank you,

I’ve attached the file (it’s a small part of a larger architectural model) in case you/others want to see it however I think both those ideas will work well.question.3dm (1.5 MB)

Hello - see if the attached version is getting close-

question (1)_Maybe.3dm (1.9 MB)

This one keeps the original terrain plus transition surfaces.
question (1)_Maybe2.3dm (1.2 MB)


Thanks for those Pascal - I want to just ‘bend’ down the loose flap highlighted in the jpg and not disturb anything else. I’ve done an ok job by splitting - the visible split is tolerable in this instance.

Your models - I’d very much like to know what you did there - it looks like methods I don’t know!


Ah, OK - the I see the highlight… hang on a bit - same basic idea as the second version I posted, assuming a separate surface is OK.

@dcooke491 - is this more like what you need?

question (1)_Maybe3.3dm (1.8 MB)


1 Like

Thank you that’s it and that’s what I’ve done.
Is there a way of stitching back together/rebuilding the split surfaces? A seam would be fine (can’t see it when rendered)

Thanks again,


Hi - You’ll probably get a very dense surface if you want to patch or NetworkSrf those together - especially with a tolerance of 0.001.

Another way of dealing with this might be to split the original terrain into two parts and then point edit only the one that you want to change. In the attached quick attempt, that resulted in one naked edge in the “support wall” direction but not necessarily something that you will notice in a rendering.

Terrain Test.3dm (897.4 KB)