Odd behavior with surface

I just upgraded to 7 from 5 a few days ago so I’m not sure if this is a bug but feels like it is-

the “what” command as well as “seltrimmedsrf” commands have always pointed out to me what was a untrimmed surface and what is not, however, I was using edge srf as usual which should have predictably gave me matching cvs along natural edges but it gave me a bunch of spans which I thought was very odd as I’ve never had this happen before unless it was a trimmed srf. Anyways, I checked my usual tools and it didn’t show any trimmed surfaces but I decided to hit “untrimall” anyways to see if anything would change and sure enough it “untrimmed 1 loops” and worked fine after that.

So my question is this a bug or are there situations where rhino won’t indicate a trimmed surface correctly? Only new command I’ve used (not sure if it was on this surface) was the “refit trim” command.

Hi Ryan - can you post the surfaces and the input curves for them?


will do!

EDIT: what was really odd is when i hit dupedge to get the curves from it those had spans as well even though you can clearly see the even cv layout. I duplicated that edge (yellow) and moved it out a bit so you can see the extra spans.

sorry let me just send the file
bad surface.3dm (5.5 MB)

So, what I was wondering about is the inputs to the surface that you do not like - the middle one - can you post all the surfaces in your image?


bad surfaces.3dm (11.7 MB)

So, Cyan is the edge as-is (DupEdge) and the red is the edge after un-trimming -


My guess of the moment is that the surface was joined to another surface(s) at some point in its life, perhaps?


understood, my question is shouldn’t it register as a trimmed surface? I’ve never had a surface that was trimmed not show up in the selection or what command so I was wondering if that was a bug.

Hmm - yeah, I guess this counts as ‘trivially trimmed’ where the edges may be different in structure from the natural edges but not geometrically different - I will consult with a bigger brain.