Have a look at :
1)Instanciating a V3d_Plane
2)V3d_View::SetPlaneOn(aPlane) activates the clipping plane;
also you can have a visual feedback of your plane by calling :
V3d_Plane::Display(aView);
Of course all of this if you use the OCC provided visualization package
PS : This is nothing more than the clipping capabillity provided by OpenGL
Commenter-1