Loft Issue

I have a simple loft issue that I can’t figure out. There was a step in a process that @theoutside helped me out with to solve a closed polysurface. I tried to re-create solving this because I tend to learn better upon repeat. I should’ve recorded the screen because I certainly forgot a simple step in this process. I’ve attached a movie to the file so that you guys could see the issue.

Any help would be GREATLY appreciated. And thanks Kyle @theoutside for your awesome help!

Here’s the video link:

Hi Chris, it really would be much more useful to post the file with the inputs to the surface you’re making.


Pascal, will do. Here it is.

I trimmed it to focus on the issue of the tenon.


I appreciate all of your help @pascal
ashissue.3dm (3.1 MB)

Hi Chris - I think I would try to structure the thing more like this:

and trim.

If I understand what you are after,

But, fwiw, I would also see if I could not greatly simplify the ‘main’ surface to avoid curvature messiness:

@Chris-Mitchell Something more like this, perhaps -

@Chris-Mitchell - this is how I’d try to lay out these surfaces.

ashissue_PG.3dm (383.0 KB)


split edge was the command we used to break up the edge and allow you to loft each part of the edge together.

you can also sweep 2 with chain edges on and use the multipart edges at the rails that are chained.

1 Like

Thanks for the tip!


Split Edge was in fact the command! Thank you. Unfortunately, I’ve run it several times and it still leaves open edges. I can’t seem to get this to close.

@pascal - How in the heck did you find the rest of my surface? I only included the cut off portion of the upper bout in my file. What kind of magic is this?

Hi Chris - trimming surfaces only ‘hides’ the bits that get trimmed off - a trimmed face is added to the document - what you see - but the underlying surface is still there as part of the trimmed face. - Untrim gets it back. See help on ShrinkTrimmedSurface as well.


you can run sweep 2 with chain on, and use the spit edges as the rails, with the clean edges as the profile curves

fwiw- Subd may be the magic bullet for these surfaces-

guitar_demo.3dm (1.2 MB)

1 Like

@theoutside . Yeah. That looks great. What does “fwiw” mean?

Also - I can’t get sweep2 to work either.

Weird. I ran untrim command and mine didn’t pop back up.

Hi Chris - Untrim works on single faces/surfaces only, so Explode or ExtractSrf your surface if it is joined in.

FWIW = for what it’s worth

" for what it’s worth"

matchsrf set to position may get you there

see attached file for my fix
ashissue_kdemo.3dm (756.1 KB)

+1 for doing surfaces like this with Subd tools! These are so much more difficult with traditional NURBS surfaces - you’ll get a better result faster with Subd’s, and way more fun to edit it that way too.

I will definitely look into that in the future. It appears that it’s the way to go.

@theoutside That was the trick!! I had totally forgotten to merge the edge and run the edgesrf command. Thank you SOOOOOO Much! Now I’ve got to look into SubD. You DA MAN!!!

1 Like

I’m using Rhino 6. How do I access SubD commands?