SubD: How do I get rid of these naked edges?

Building a simple shell by extruding edges in SubD box mode. Get to this point and cannot close the indicated naked edges between ceiling and walls. I must have missed the SubD 101 where this was covered - what do I do?

Stitch up.3dm (1.4 MB)

Hi Jeremy - I am not sure why it is this way but you can fix it by ExtractSrf the underside and the vertical edge faces, and rejoining these back into the rest.



Hi Pascal,

Thanks for the workaround. Thinking about why there is a problem: it might be because stitch doesn’t work for a pair of edges adjacent to a joined vertex. If I reduce the faces to this

I still can’t stitch A but I can stitch B. If I swap to smooth view and turn on control points there is obviously a difference between the corners, with a stitched vertex at one end:

An unstitch command would be helpful here…

In a separate test I placed two SubD planes together:

Having stitched 2, I cannot stitch 1 or 3, but I can stitch 4, further proof of my hypothesis.


Hi Jeremy - yes I see and in testing, it seems to me to be a bit finicky to even Stich edges that are on top of one another at all - is that your experience?


Yes absolutely, it can be deeply frustrating. But because I am new to this and experimenting to find the best way to do different things, I’m never sure to what extent I am struggling because I am approaching something in the wrong way or to what extent SubD isn’t ready for what I am trying to do (which in this case is different to what I see in @theoutside’s videos where he is riffing off SubD so creatively - I’m trying to produce models that conform to all sorts of dimensional constraints). Anyway, in respect of stitch, here are a couple more frustrations:

Post-selection needs to be more user-friendly: when you have to select the second edge it isn’t helpful to be presented with a list of edges including the edge selected first (without anything to say which is which).

Often after picking (I think) two edges I just get an error message telling me the count is wrong. That may be because I picked the same edge twice or because a vortex is being rolled up with the edges, or something completely different - to be user friendly the message needs to be more informative.


Right - that should not be allowed - I made this earlier:
RH-62027 Stitch: Edge selection tricky


Has this issue moved forward or is there a workaround building this surface some edges stitch together no problem others refuse am I missing something else which would seem to be a simple workflow.

Hi Alex,

According to youTrack this is scheduled for 8.x so don’t expect anything in 7. In the Beta, the first pair of edge sets you pick to stitch now show arrows to indicate which edge you are picking, subsequent pairs unfortunately do not. You still can’t stitch meeting edges adjacent to a stitched pair.


  1. Stitch an entire seam in one go instead of one pair at a time.
  2. Move the face(s) on one side of the seam slightly, so the edges are no longer coincident, before stitching.
  3. Stitch vertices instead of edges.


Thanks for letting me know using the layer difference method for the moment v8 fix is the logical workflow. regards Alex