What you do is: 1) move the cylinder so that it overlaps/ intersects the cube 2) select one object (the cube), then hold shift and select the other one (the cylinder) 3) In the toolbar at the top go to Polygons/ Booleans/ Difference And that should do it Try experimenting with the Union and Intersection settings and which item you select first; you'll get a lot of results to play with! Good luck!