Unable to join untrimmed surfaces

After importing a model I found I could not join several surfaces. I untrimmed the surfaces and now I can see there are at least two places where there is a gap between the surface edge curves. I have tried using network curve but it does not take. How can I fix these gaps so I can join the surfaces (blue and orange).

Hi Jeffery- MatchSrf is probably what you need- there are a number of settings in the dialog, so pay attention to those - depending on the desired results…


That does not seem to work as I cannot select the surfaces. I tried to attach the file so you can take a look but it is 9 megs and dont know if it will post.

Please send via www.Rhino3d.com/upload, to my attention (Pascal), I’ll take a look - or maybe simpler, export a couple or three of the surfaces that do not work to a new file and post it here- either way.


Thanks. I didnt know you could export surfaces. It made a much smaller file. See if this is attached.

Surface join failure.3dm (107.5 KB)

Those surfaces joined just finely.Surface join failure.3dm (102.5 KB)

I see… this is going to be a bit painful I’m afraid - the surface you sent are not untrimmed, they were trimmed and joined into polysurfaces- that is why MatchSrf was not allowing selection. It looks to me like the intersection curves are pretty far off in some places- like the vertical fillet surface and the object below, that it may be meant to join up to - CrvDeviation on the edges there shows quite a gap - .039 units


Yes, that there are several places like this that need fixing.

Perhaps it would be good to back up here. Maybe I am using an ineffective workflow. This file show the unaltered import from SolidEdge. I want to extract the outside surfaces, join them and fillet the corners so I can offset as one surface. The first thing I did was untrim the surfaces which started my problems. Is there a better approach?
Model import.3dm (221.3 KB)

Hi Jeffery - There is some tricky filleting there… is SW not able to do it to begin with? That would be best if it can, otherwise Rhino can certainly make the fillets, but it will take some hand surgery to clean up. How big are the fillets and how much is the eventual offset?


Ok, I went back to SolidEdge and made a few changes and it fixed the previous problem. Offseting the surface now looks generally good except for one area which is in blue.
Can you say why it is kicking out this area? The layer ‘dome surface’ shows what the offset was made from.

Model import 2.3dm (783.7 KB)

Yeah - that is a messy corner - try adding a couple of faces

you’ll still need to clean up a little but it might be a better start point.

Here is my result- dunno if that is what you were after…

Offset_PG.3dm (381.8 KB)


That looks great and is usable for bringing it to t-splines which I know even less about. I will try and recreate what you did in Rhino first. Thanks