Question regarding the tool "retrancher les surfaces" which should be translated by "substract surfaces" in english

[PauleSud]

Hi, I'm working on a 2D drawing of a section of a building. I want to integrate some objects (drawn with CAD) inside the colored surface of my rooms, and the surface of these objects will have its own colors. So that the colors of the room and the object don't overlap, I want to subtract the surface of my object from the surface of my room. But when I click on "subtract surfaces", my object disappears. 

 

Does anyone have any idea how I can solve this problem?

 

 

 

[bcd]

It sounds like it might be a stacking problem where you are subtracting the room from your object not the other way around.

Make sure that the new objects are placed last and on top, you can Edit>Cut then Edit>Paste in Place to achieve this.

 

 

[PauleSud]

Thank you for your answer. I didn't find the problem, but I was able to solve it by working around it. So I removed my background surface, drew my object and its surface, then added the background surface with the space left in the room. 

[bcd]

Good to hear &  if you are interested in getting to the bottom of it for the future you can post a file with the problem and we'll help you figure it out.