I am trying to make a mold of my assembly (a tap/faucet) in two cuboids (one either side), however since my assembly has chambers going through the insfide of it, when i use a cavity or indent feature it does not cut the whole way through, it only cuts in the thickness of the outside surace and doesn't cut the shape of the inside. How do i completely cut out this shape. also i have the student edition and when i'm in assembly it does not let me use the mold tools on the assembly as a whole only individual parts. Thanks