How To Upload With Holes In Model?


When I upload my .stl file, it uploads the file but without the booliens (holes) in it. I’m using FreeCAD. Also, I just select all the parts of the model and save it as a MESH file to upload. Is this the wrong way of doing it?

Thanks in advance


Hi ASee,

FreeCad is a bit unexplored territory for me, however
There are a few possible reasons :

  1. something with the boolean operation in FreeCad -> consult their community ?
  2. something with the export to stl file format -> try another file format ?
  3. the stl file might not be waterthight and so our software is repairing the model and fills the hole…-> do you see the word fixing after analyzing during the upload ?

Kind regards,

Did you preview your .stl file (view3dscene, meshlab, meshmixer,…) before uploading to make sure that the holes created by the Booleans are actually in the exported model ? (I have not used FreeCAD for some time, but I seem to remember it was necessary to invoke Part->Union after selecting all parts and before writing the .stl)

Hello wim.verstraeten,

I do see that it says “fixing”, and “medium fixing.”
How would I make the .stl file watertight? Would I have to extend the object holes past the object that they make a holes through?

Hello mkroeker,

I do check on other 3D previewers. It comes out without the holes.
So would I try “PART Workbench” and then click on “Make a UNION of several shapes”?

Yes, that is what I would try. You need to get to a point where you actually see the holes in a previewer.
(At that stage it is still possible that the mesh has some irregularities that a previewer may not pick up - tiny overlapping triangles or triangles missing in the mesh. The site software will try to fix these automatically but may not always choose the correct solution. So it may still happen that holes you see in a previewer get “papered over” in the automated fixing when the software picks a vertex on the other side the opening instead of an adjacent one. There are tools to help with fixing that as well)

Hi ASee,
I could have a look at the stl file if you send me the link in a personal message on the forum.
However if you do not see holes in other viewers, I believe the solution is somewhere to be found in FreeCad .

Hi wim.verstraeten,

I figured it out! Thanks so much for your help!

Have a good day,


Hi mkroeker,

Thanks so much for your help! I finally got it!

Have a good day,