Subtraction of two objects

Hi,
I am new to Unity3d.With the help of tutorials , I am able to make triangles and semicircles as gameObjects.
Now i have to subtract one object from other if they overlap. I am dealing in 2D.

I am posting the link of exactly what I want, in case, i am not not able to explain it properly.

http://www.illustratortips.com/index.php/Instruction/Intermediate-Tips/how-to-use-the-illustrator-pathfinder-palette.html

 

Hey,

I think your looking for something like http://forum.unity3d.com/threads/85713-Boolean-Subtraction-Operations-on-Mesh.
Here is a video aboat that post: http://www.youtube.com/watch?v=kcsF_EhCVPI&hd=1&fs=1&autoplay=1.
Maybe you can get some information from these. (I did not check, these are the first things that came up with the search engine)
This is a really fun project your working on, but to be honest what your trying to do is kind of hard to start out with.
Hope it works out.

 

i dont get why a thing this simple is not included in unity. the simple act of cutting a window from a wall becomes tedious.