Here is my situation:

I place a cube of 20mm and then a cylinder of 2mm diameter and 22mm length through the center of the cube, extending 1mm from either side.

Using the cube as the "master" and doing a boolean difference with the cylinder works fine. The shaded model correctly shows the cylindrical hole through the cube.

I apply all transforms then do an STL export to view in either MS 3D Viewer app or CURA. Both apps show the cylinder ends protruding beyond the cube faces on opposing sides, no hole, just the cube face.

I also tried snapping the cylinder ends to the opposing cube faces in edit mode, then boolean difference in object mode. Blender displays it correctly as in the above procedure. Export STL and view in CURA et al, same result. No hole through the cube, in this case just 6 empty cube faces.

This is a simple example of the problems I'm having with a more complex model. Blender shows all the boolean differences correctly (3D Tools has no complaints) but the holes in cube faces and vacancies that should occur in the volume of the cube do not (render?) correctly in Cura or MS 3D Viewer.

I'm stumped! Is there a way around this situation?Cura render of first procedure

Thanks for your help! Dave

  • $\begingroup$ Did you delete the cylinder before exporting? $\endgroup$
    – John Eason
    Commented Aug 31, 2023 at 20:10
  • $\begingroup$ Hi @Peter, no, but I do make the eye icon in the collection off. $\endgroup$
    – Sonar Dave
    Commented Aug 31, 2023 at 22:19
  • $\begingroup$ I did a boolean union, with the cylinder normals reversed. Then keep (eye icon open) the cylinder active. Works great. Then I applied what I learned to my project, works. The suggested procedure did not work for me, alas. $\endgroup$
    – Sonar Dave
    Commented Sep 9, 2023 at 21:08

1 Answer 1


I believe I found a good answer to my own question.

I used the Solidify modifier, 1mm with offset of -1. Then I had to delete a face in the cylinder on one end, now it shows correctly in MS 3D Viewer. I still have to try it in CURA, but I think it will work.

BTW, I found that solution in a web search for boolean not working in CURA. LOL,


  • $\begingroup$ Nope, although it shows correctly in MS 3D Viewer, it does not in CURA . The cube face where the through-hole should be is solid, shows extrusions on the entire face. I gues this is now a CURA issue, so I'll take my problem there. Thanks for bearing with a NOOB $\endgroup$
    – Sonar Dave
    Commented Aug 31, 2023 at 22:42
  • $\begingroup$ I'm John, not Peter <grin>, but turning off the eye icon will only stop the boolean object being shown in the 3D viewport, it won't affect whether it's exported or not. Once you've applied the Boolean modifier you can delete the cylinder altogether. $\endgroup$
    – John Eason
    Commented Aug 31, 2023 at 22:44
  • $\begingroup$ Hi John, sorry I picked the wrong name from the page. That's a great suggestion. I didn't because I like to leave the option to edit the parts later, but I can make a "printing" copy and use your idea. Thanks! Got my printer yesterday, calibrating... $\endgroup$
    – Sonar Dave
    Commented Sep 4, 2023 at 3:24
  • $\begingroup$ Yes. I should have said that you need to keep a seperate copy of the Blend file in case you need to change it later. Good luck! $\endgroup$
    – John Eason
    Commented Sep 4, 2023 at 8:06
  • $\begingroup$ Hi John, if I delete the cylinder, it no longer is in the file. That is, delete and it disappears from the cube in the 3D view. The cylinder is a boolean difference from the cube, so that it will exist inside the volume defined by the cube. $\endgroup$
    – Sonar Dave
    Commented Sep 8, 2023 at 20:07

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