3D Printing and Booleans

I started using Cheetah 3D when I was doing game design and have continued to use if into retirement to create 3D models for 3D printing. I really appreciate the ease of use but booleans are causing issues for 3D printing. The problem is that resulting object in not always “watertight.” There are often internal triangles, manifold edges and missing triangles. Polygon optimize can generally correct the missing triangles but the other two issues aren’t handled. This results in a part that is unprintable without processing it with a separate application. Normally I do this with Shade 3D as it has a very good 3D printing module to correct much of this. However, it’s far better at correcting models created within Shade 3D than it is when the models were created elsewhere.

Is there a way to improve the resulting Boolean generated surfaces? Barring that, is there a possibility that the optimize function for polygons could be improved to address common errors for 3D printing? I feel you are missing a great opportunity for future sales given the growth of the 3D printing community.


Active member
Hi mperdue,

Are you using v6 or v7? v7 has an updated Boolean algorithm. I'm not saying it isn't some other problem, but that may help figure out what the problem may be.

frank beckmann

Well-known member
I guess you´re using text-splines/extrudes with bevels inside your Boolean hierarchy? Currently there´ s no way to clean-up the overlapping/self-intersecting geometry. Can Shade3d eliminate this kind of issues?

No, I use mostly simple geometry, cylinders, tubes, cubes and spheres but the parts do get pretty complex. I build models of various items from the US space program. Most of the time, Shade3D's 3D printing check can find the errors and can often even correct them. As I stated, the problems are mostly related to internal triangles, manifold edges or missing triangles. The missing triangles are something that Cheetah 3D's optimize does a good job of fixing. The other items cause serious printing issues.

frank beckmann

Well-known member
In order to create a useable STL file I select "Make Editable" and export the STL. The resulting files have the errors.
I meant the Triangulate feature of the Boolean-modifier/creator and there´s an additional Triangulate-modifier. Do you use the standard scale for export?
PS.: I´d ry to triangulate before exporting to check if the on-the-fly exporter is causing the issue.
Totally off topic but Cheetah 3D is the only app I've run that has managed to use all 8 cores at 100% on my iMac Pro. I was impressed.
Martin put lots of effort into multithreading. ;)

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Let me do a little testing today with and without the triangulate option selected in the boolean modifier. Before I do that, one question. In earlier versions I had to make the item editable prior to exporting the STL file. Is this still required? My workflow would be much better if I didn't have to do this but it would result in all the merged items being output, even the subtracted ones. That was a mess.

frank beckmann

Well-known member
I once made a file for the Help. Go: Main menu->Help->Cheetah3d samples->Modeling->Booleans.jas
Open it and go shift+E for export: blablabla.stl and you´ll get a watertight stl-mesh:

Using that part by just opening it and exporting it as and STL I find 98 Overlapping Elements. 1 non-orientable surface and 24 non-manifold edges. All are correctable by Shade 3D's 3D Printer helper.

If I enable the triangulate option in the booleans and export the STL I get 207 overlapping elements, 1 non-orientable Surface, 219 non-manifold edges, 6 discontinuous faces and 29 internal faces. Again, Shade's 3D printer helper can correct all these.
And one other test. With triangulate off in the booleans I selected make editable and then exported the STL. This results in the same file as the first test in my last message. That would seem to indicate that the triangulate option is adding some issues but there are issues without that. On the bright side, now that I don't have to make everything editable before outputting will save me some time.

frank beckmann

Well-known member
Using that part by just opening it and exporting it as and STL I find 98 Overlapping Elements
This seems odd - I´m not able to find these.
1 last test is to make editable then triangulate and then export to see if there´s a difference in the on-the-fly-export process probably.

Triangulate off, make editable, triangulate then export to STL. This gives 39 overlapping elements, 36 internal faces, 1 non-orientable surface and 121 non-manifold edges. All errors are correctable.
When my printer completes what it's doing I'll try using the files without the "make edible" process to see if they can be printed. I don't much care if they are perfectly formed files as long as they can be used to print my parts.

frank beckmann

Well-known member
Strange numbers though. Not sure if Martin has plans for a more streamlined 3d-printing output.

PS: my Shade3d for Unity doesn´t have such 3d printing features.
I can’t speak for anyone else but one user would appreciate anything that can be done to help 3D printing support. :) I appreciate your help.
Just an FYI, I ran the STL through meshmixer before loading it into Shade3D and it comes up clean with no issues found by 3D helper.