A clever way to close a volume


I am searching a smart way to add 2 surfaces to each of these beams to have a 4 surface beam, I mean something kind of closed.
I tried like this: I exploded the mesh and then tried to extract the edges of the mesh to create side surfaces but duplicate edge didnt worked.
I also had a look into the “close planar surface” but didnt work.

Any idea? :sunny:
thanks :smiley:
pb_close_volume.3dm(224.5 KB)


Try this:
Explode mesh to separate the bits out you want to close,
Extract mesh edge,
Draw missing lines to form closed polylines,
Mesh from Closed polyline,
Join Meshes.


I tried to extract the mesh edges after explding the block, the extract mesh edge asked me for:
unwelded or draft angle, with select edge of 180 , etc. I clicked a little everywhere :wink: trying different options but couldnt extract any edge of that mesh, dont understand if I am doing wrong of if that mesh is kind of a problem

(Pascal Golay) #4

Hi Flo- Use FillMeshHole for this,



Hi Pascal,
mmh, also didnt manage with this one :-/ one strange thing from the beginning is that I couldnt extract the mesh edges…
the file is in the post, could you have a look at it?
I launched a checkmesh, it looks to be a good mesh…


(your file contains 2 same overlapping mesh objects so delete1)

  1. Run MeshRepair
  2. Press Check Mesh and Repair Mesh, then Next.
  3. Check (48) Disjoint pieces box, click on Repair and Finish.
  4. Click on open beam mesh and run MeshToNURB command.
  5. Select created polysurface and run Cap command.
    Hope this helped

There should be a CapMesh command for such situations.


Here, just deleting the extra copy, then using FillMeshHole worked. It welded the edge so it looked weird, though, so I unwelded afterwards.pb_close_volume_HS.zip(104.1 KB)


thanks for your post,
I don’t have the Repair Mesh function, it must be in Rhino 5 I think,
I went around the problem by created an approximate surface from the side view port and using it as a cap,
I didnt find any other way :wink:
kind regards,