Since Siba didn't feel like explaining.You can convert saves to OBJ aand then to BLB. BLB has a limit of 10 cuboid collision boxes.
keep repeating that and then you could make a one brick house(make part of it with 10 bricks, make that into a blb, put that in a save and add to it and then repeat)or would that work?
you missed the part where blb bricks cant have more than 10 collision boxes