I seem to have a problem with subtracting from a bsp brush. If i create a cube as additive and then create a smaller cube as subtractive to cut out the first cube, when i move the subtractive brush out of the way the original is filled back in again. I’ve also tried building the geometry and that doesn’t help either. I’m sure i’m missing something really simple, but the last time i used unreal was way back in the 3.0 days and lots seem to have changed since then.
Not Sure if this is the right way or the wrong way but once i had both additive and subtractive brushes in place I merged the two into a static mesh which gives me the complete shape i was looking for.