I'm new to Blender and unsure if this a bug in the beta version or my error. I can't make the union boolean modifier work. It does nothing visible.

Setup: I created an svg file and imported it. I then converted the curve to a mesh. Since it has several discontinuous parts I selected the linked parts of the mesh and filled them. Then I extruded the mesh to get depth. I intend to 3d print the result so the separate parts needed to be joined. I created a cube and scaled it to use as a connector. I duplicated the result and moved them into place. I selected the shape and added a 'union' boolean modifier. The first cube worked. The other cubes do not work. Picture attached.

What I checked: I believe the meshes are closed, water tight, and the normals face outward. Any other suggestions?

blender file

image of the blender screen

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    $\begingroup$ You have set your Clip Start to something insanely small. That will probably fix your view port to start with. Then you can upload your file so we could investigate further. $\endgroup$
    – Jackdaw
    Commented Mar 3, 2019 at 22:25
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    $\begingroup$ Added link to the post. Thanks for the help $\endgroup$
    – Jay
    Commented Mar 3, 2019 at 23:05
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    $\begingroup$ Just use the fast-boolean addon, its better anyway $\endgroup$ Commented Mar 7, 2019 at 0:05
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    $\begingroup$ Usually boolean addons use the same libraries as standard modifier (or use modifier under the hood) so precision errors won't be fixed $\endgroup$
    – Mr Zak
    Commented Mar 7, 2019 at 13:46
  • $\begingroup$ @MrZak well this addon has its own code, so just no $\endgroup$ Commented Mar 7, 2019 at 23:19

1 Answer 1


the problem is that you have overlapping faces on the bottom of your mesh.

enter image description here

in this example i create 2 cubes and try to make a union operation but it doesn't work because the cubes faces overlap when i scale down one cube the union operation works as expected.

good rule of thumb if you work with booleans if you have a problem try to move one mesh until it works.


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