I am quite new to CGAL as well as OpenGL. I know that CGAL provides a Qt interface to display objects but I want to use only OpenGL and I am able to render polyhedrons and nef polyhedrons in openGL(I referred to polyhedron demo). Question is, how to display polyhedrons of different size efficiently in openGL. I apply translation in my program using glTranslatef to view the objects properly. Problem is, it may not work for each and every object because of the difference in the size. Therefore I need to apply translations based on the size of the object. If I can find the longest diagonal of the object this may be possible by adjusting the value of the parameters that I pass to glTranslatef(). Is there any way to do this in CGAL?
Treat your objects as a collection of points, and create a bounding volume from it. The size of the bounding volume should give you the scaling required. For example, you might wish to center the view around the center of the bounding sphere, and scale the view based on its radius.
See the chapter on bounding volumes.
Also, you probably want to use glScale to scale the view in addition to glTranslate to center it.