Hi!
I create my viewing volume with:
gluPerspective(angle, (GLfloat)w / (GLfloat)h, radius/100, 3radius);
Then i wanted to create a quad at the near and at the far plane, which fill the whole plane. I thought that the width
and the height on the near plane are:
heigth=tan(angle)radius/1002
width=heightw/h
and for the far plane:
heigth=tan(angle)radius32
width=heightw/h