Patent US 5,124,693

A user interactive computer graphic display which generates three dimensional perspective projections of graphics objects. The user can specify the location of the vanishing point of the perspective projection before or after the generation of the graphics objects on the display. Moreover, the vanishing point can be moved by the user resulting in the simultaneous changing of the perspective projection of the graphics objects so that the most pleasing three dimensional display can be achieved. The user may specify a length of the projection lines which defines the depth of the three dimensional projection, or the user can accept a default depth. The entire editing set available for editing two dimensional graphics objects is available for editing the perspective projection of the graphics objects.