I have created some cylinders, removed the top and bottom faces from them, and used the solidify modifier on them.

I am trying to remove a section of the outer cylinder by using a cube of the exact size I want to remove. I thought that using the boolean difference modifier would work but it creates a sort of half union effect.

I can achieve a close result by subdividing the cylinder, moving the edges and then removing the faces, but it is not as precise as I was hoping to achieve.

I have provided some pictures of what I am trying to do and what is happening. Is there a better way for me to achieve this?


I want to remove the section of cylinder that intersects with the cube.

Here is what happens when I try to use the boolean difference modifier.

Here is what I am trying to achieve. This example is the wrong size cut out. I am looking to cut a piece out of an exact size, thus why I was trying to use the cube.

  • $\begingroup$ Subdividing is not as precise? Why that? I think you should try this way and avoid boolean as much as possible (even if I don't understand why it didn't work for an as simple operation) $\endgroup$
    – moonboots
    Aug 31, 2018 at 9:04
  • $\begingroup$ Well, I don't know how to make sure with subdivision it would be the correct size that I need. I know that the cut out edges need to be 1 grid square apart, straight not curved. From what I could gather with the boolean difference, it seems to get confused when two of the edges are open. If I close the two open edges when performing difference it works but then leaves those extra edges. I guess I could remove them manually afterwards. I was hoping to minimize the number of steps required if there was a simple solution. $\endgroup$ Aug 31, 2018 at 9:18
  • $\begingroup$ I intend on repeating this on multiple locations of the cylinders and I was looking for a way to maintain consistency of size between all of them. $\endgroup$ Aug 31, 2018 at 9:22

1 Answer 1


You can use the boolean / difference no problem.

It is such a simple shape that it will still be good topology after you apply the modifier. The reason that you get the hollow cube thingey, is that the two shape have exactly the same height. Weird stuff comes from 3D programs that will have to calculate difference between 2 items witch are the same location. If you scale the box on positive Z just a bit, it will work perfectly.

Usually I don't like boolean because it trashes the topology, but in this case it fits the part!

  • $\begingroup$ So I guess, i'll just have to remove the top and bottom parts manually afterwards if I don't want them or just change the z axis ever so slightly that it won't make a difference? $\endgroup$ Aug 31, 2018 at 9:47
  • $\begingroup$ scale the z axis on the box just the slightest bit should do the trick $\endgroup$ Aug 31, 2018 at 9:48
  • $\begingroup$ If you keep the boolean modifier and do not apply it, please note that the box will still be visible, so you can hide it, or move it to another layer and hide the layer. $\endgroup$ Aug 31, 2018 at 9:50

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