This will create a reverse/ negative design for use as a mould or similar
To do this we use the combine tool which is found in the Intersection menu
To start I draw two shapes, one will be the base (1) and the other the cutter (2)
I then move the cutter in to the base
Selecting the combine tool from the intersection menu
I select the base and then the cutter, this then creates a third object which is the waste material. Notice the saw against the cursor when selecting the cutter object.
I can then delete the waste material and the cutter object to leave the base with a negative object of the cutter.