Nope. All slicers work by intersecting a plane with a 3D volume. In this case a CSG tree. At the bare minimum you need a way to tell if an x,y,z point is inside

Nope. All slicers work by intersecting a plane with a 3D volume. In this case a CSG tree. At the bare minimum you need a way to tell if an x,y,z point is inside the volume or outside. In the case of a rotated cube shape, the x,y,z vector is just rotated/transformed the other way (inversely) than the cube, and the test still works. Most slicers will have more sophisticated methods of intersecting a plane with a volume...