A stereoscopic image generator for superimposing a stereographic pointer video signal onto a composite standard video signal, the genrator comprises a computer for generating the stereographic pointer video signal in response to an input signal representive of the three dimensional coordinates of a point in a three dimensional video image, a video synchronizing circuit for receiving the composite standard video signal and delivering a synchronization signal to the computer, and a video keying circuit for receiving the composite standard video signal and the stereographic pointer video signal and superimposing the stereographic pointer video signal onto the composite standard video signal to produce a single combined video signal, the single combined video signal allowing the stereographic pointer video signal and the composite standard video signal to be viewed together simultaneously on the same video screen.