I am having issues with some non-manifold geometry.. I understand there are a few types or a few sources of non-manifold geometry, but I can't find the exact issue with my model..

I noticed most of it, if not all, was located where I merged vertices together. Why would this cause non-manifold geometry? I thought the goal of the merging process was precisely to make sure I had a unified mesh?

Here is the file in question, maybe I missed something:

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    $\begingroup$ Hello :). Merging vertices can still leave interior faces, or double edges. Please add some images (and perhaps your.blend) if you want more specific answers :). $\endgroup$ Commented Aug 5, 2020 at 8:58
  • $\begingroup$ Thanks for the response! There don't seem to be any interior faces and I have already tried to merge by distance to fix double edges but there doesn't seem to be any... How do I add my .blend to the post? $\endgroup$
    – DCardinal
    Commented Aug 5, 2020 at 18:23
  • $\begingroup$ Hey :). You can try gdrive/dropbox or our local blend-exchange. $\endgroup$ Commented Aug 5, 2020 at 18:24
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    $\begingroup$ @JachymMichal Awesome, went ahead and did that $\endgroup$
    – DCardinal
    Commented Aug 5, 2020 at 19:20

1 Answer 1


Your mesh contains flipped faces, which is considered non-manifold geometry.
It's probably not caused by merging vertices, and it's easy to repair

  1. Select all faces
  2. Go Mesh > Normals > Recalculate Outside
  3. Done.

After this, there are still some non-manifold vertices on the outer rim, because the mesh isn't 'closed'.

enter image description here

  • 1
    $\begingroup$ Amazing. I thought I had already fixed those... Apparently I hadn't! Thank you for the help, cheers $\endgroup$
    – DCardinal
    Commented Aug 5, 2020 at 19:46
  • $\begingroup$ Glad to be of help :). Good luck with your project. $\endgroup$ Commented Aug 5, 2020 at 19:47

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