How do I use the subtractive brush?

When I bring in a mesh and make it subtractive it still wont subtract from my landscape …is that possible if so how is it done??

Thank you.

BSP objects (shown in the Geometry mode tab) can only be subtracted from other BSP objects. Subtraction doesn’t affect terrain or static meshes, sorry for the confusion.

Ah. Ok then. All is well. thank you.