Cutting Mesh breaks Union Overlapping Volumes

[FluffRat 0]

I am trying to print an art asset sculpted with multiple meshes. It does not respond well to remeshing but tests using Union Overlapping Volumes look good. I also want to embed geometry created in CAD as a negative, but when I try to boolean the objects by adding a cutting mesh (set to 0 walls, 0 top, 0 bottom, 0 infill) the sculpt object slices as though the required union setting wasn't checked.

 

Checking Union Overlapping Volumes in the cutting layer as well had no effect. I tried the infill subtraction mode also just for troubleshooting purposes and it does seem to function as expected (although it does not do what I need, obviously).

 

If anybody has a clever solution I'm all ears, been up all night failing to solve this puzzle. The original file is somewhat cumbersome, so here is a simple test setup.

bugreport_subtracting_object.obj bugreport_composite_object.obj

[FluffRat 0]

I found sort of a work around thanks to this old closed support ticket that pointed me in the right direction: https://github.com/Ultimaker/Cura/issues/5461

 

Union Overlapping Volumes silently fails when cutting (or support blocking according to the ticket) is applied. It also doesn't work for discreet objects in the object list, but rather than treating the boundary as XOR in that case it just overlaps them (duplicated infill and all).

 

This allowed me to go into the sculpting program and export the file 5 times with the overlapping meshes deleted, and then manually line them back up in Cura to produce something close to the original art. One of the sculpture elements had non-manifold geometry that I was unable to remove, but it doesn't touch the internals and I think it will still print given the overhangs.

 

The resulting print will take about 5 days 17 hours and 912g due to the overlaps all having their own walls and infills, which is about %50 more than the remeshed version, but at least this should be possible to print without sacrificing exterior geometry quality. I guess I'll know if it worked next week...

[FluffRat 0]

 

Turns out I was missing this option before...

 

After a couple failed prints I went back through looking for anything I could tweak and saw this. Turning on Remove Mesh Intersection makes for much better internal geometry while using the multiple files workaround.