The mysterious hole

I've created a hollow object with a Boolean Difference, but it has left a hole in the mesh that I can't seem to fix. There are no vertices on the periphery of the hole itself, and it extends across two faces at right angles to each other.

When I look inside the hollow (as far as I can), I see that there are "shadow" connections between vertices that I would have expected to be unrelated.

I've tried manually reducing the NGON faces to quads and triangles, but it's had no effect on the hole. I've tried Mesh > Cleanup > Fix Holes, also with no effect. I've tried to Beautify the affected faces, again with no effect.

I've attached a link to the file in a state prior to my messing around trying to fix it (approx. 10MB)

Link to the .blend file, approx 10MB


2 Answers 2


You have some manifold Geometry inside of your mesh. You can select the affected edges or vertices with Ctrl Shift Alt M in Edit Mode:

Non-Manifold Edges

You need to delete every connected Face and readd it manually in a "logical and watertight, clean" way.

After you corrected this - you need to delete this one face which isn't connected in one flat plane but with many of these vertices that got selected - you will get quite a clean tank model without holes ;-)

Tank Model without holes


There is no hole in the mesh, but a non-planar n-gon (a polygon with more than 4 vertices) that is ovelapping on top another face.

You should delete it and try to reconnect the remaining geometry using quads...

enter image description here

  • 2
    $\begingroup$ Using Ctrl+T operator will triangulate Ngon which can be converted to quads after, this can allow skipping deleting face. $\endgroup$
    – Mr Zak
    Commented Mar 3, 2016 at 20:31

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