I'm struggling with a what seems like a simple task, both in an animation sense and a 3D printing sense. I'm attempting to create a model similar to what I'm showing here that would allow me to take a point source of light and run it along the interior of a "blue glass" material. Here's my steps so far...

  1. I created the circles with the circle curve.
  2. Added depth to them, made them full, etc. in the object data panel.
  3. I converted them into meshes.
  4. I joined them all into one object.
  5. Used edit mode to remove and doubled vertices.
  6. Created a larger square and did an intersect boolean to attempt to get only a single layer of mesh...didn't work.
  7. Created my material and added lights.

You can see when I have the light in a part of the model that has no interior faces then it fully shines down the tube. When it's behind or in an area where there are interior faces they occlude the light.

Is there anyway to make Blender behave as if the whole object is solid even if it isn't? I understand the best way to achieve the look I'm wanting is to have no interior faces, but that seems to be an impossible task given the modeling that I'm doing. This example is a heavily simplified version and the full model has many more layers of circles at descending sizes.

I'm also running into this problem with creating these models for 3D printing. The interior faces are a real problem that I can't seem to overcome.

I've got two images attached, one showing the lighting issue, the other showing a fuller version of my model. TIA

enter image description here enter image description here

  • $\begingroup$ In any of these attempts, did you try to use the Select menu (in the header) to select Select All by Trait -> Interior Faces and then delete the selected faces? $\endgroup$ Sep 25, 2021 at 21:41

1 Answer 1


This should probably have been a comment, but I can't create those for now...

If you want to combine objects while eliminating the interior surfaces, the boolean 'union' operator seems the most appropriate to combine your circles. This operator removes internal faces (creating vertices where needed).
It's probably going to be quite fastidious to do, unless you can do it in stages where you combine a few tori, and then duplicate those units (e.g. create units of 4 red circles and one purple).

  • $\begingroup$ Yeah, boolean was my first attempt. Utterly fails in most of the unions I need. $\endgroup$ Mar 20, 2018 at 15:27
  • $\begingroup$ there are two algorithms for the union operator, one of them removes interior faces, the other doesn't $\endgroup$
    – remco
    Mar 20, 2018 at 15:58

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