I am using the subtract difference function to make a walk way. First I made a Poly cube then I made a cylinder with 40 sub divisions. I went to face mode and cut the buttom half off. Then to edge mode where I pulled the buttom downwards to create a sort of door/archway shape. Set both pieces of geometry to zero. Scaled them to where I wanted to to be and clicked on the cube shift clicked the cylinder, and proceeded to execute the command. Here is what I got, and I am sure it has somethign to do with volume however I do not know how to fix the problem.
Boolean subtract not working as expected
Let's see if I can help you find the answer.
Make sure the cylinder is a little more below the room and that the depth of your cylinder goes beyond the depth of your room as well. Select the room and then select your cylinder created.
Select Boolean. Set/Change the Operation from "Union" to "Difference" and set/change the Classification from "Normal" to "Edge"
-Line
See image for result:
