To cutoff portion from a object

I am creating simple 3D application. Showing some of the objects such as Rectangle, Triangle etc.

Now I want to cut a portion of an Object and want to make the cutoff area transparent so as to view the other objects from the transparent portion.

For e.g.
Consider A is Rectangle
B is Quadrangle and
C is Circle.

A is on the front screen
C is behind A.
So when I view directly I can see only A, until I rotate, I am unable to view C.

Now, I want to cut B size object from A, making Quad size hole in A, so that I can view the portion of C object from the hole.

So, I want to know from OpenGL Experts is there any in-built functions or properties through which I can cut object using another object and Can I make the cutoff area transparent so that I can view portions of all other objects behind the cutoff area from the cutoff portion.

Please write back to me at

Deepa Nomula.
Software Consultant,
CyberMarine Knowledge Systems Pvt. Ltd
Navi Mumbai

This is not an advanced question.

Do a search (on google and this forum) for “CSG”. You can do what you want in a number of different ways (stencil, depth test, CSG) but learning about CSG methods will probably give you the larger benefit.