3D coordinates system ??

i’ve some problem with 3D coordinates system.
I don’t find how can i do to retrieve the position of the camera from which the scene are calculated. Someone can explain me How the coordinate system work for camera ??

Try to add gluLookAt function which will tell the position of your camera/eye.
(If this is not the required answer,please explain the problem )

Many transformations ( translation, rotation and scale ) are apply by user to the scene and, i want to retrieve the camera view in the modified scene !! How can i obtain the viewpoint because after i must send it to Acis modeler in order it calculates hidden or visible lines ? I had no problem with Parasolid because it uses the same method as opengl ( i just send it the modelview matrix ) whereas i don’t how can i make with Acis.

[This message has been edited by ahryman (edited 11-19-2001).]