I have a small and simple model with 3 pieces that I am trying to put together, so that I could 3D print them (export to STL). The middle part, a mesh created by subtracting two polysurfaces from a polysurface, will not union with the two pieces on the sides. I tried turning the pulysurface into a mesh, ran a check for naked edges etc, but I don’t seem to find any problem that might be causing this.
I tried so many different sequences in producing these geometries (first subtracting then joining; first joining then subtracting, making holes later etc) and sometimes there would be a strange result from the MeshBooleanUnion command: surfaces on both objects would disappear.
There is probably something essential that I don’t understand about meshes and their union. Any help would be much appreciated!
I am including the file here: ununnionablemeshes.3dm (2.7 MB)