Introvision was a variation on a front-projection process that allowed film makers to view a finished composite of live action and plate photography through the camera's viewfinder on set and in real time.
Done well, the illusion was nearly perfect, particularly with precise lighting and careful miniature set construction (or previously photographed images, which was done in The Fugitive with a train superimposed behind actor Harrison Ford).
The front projection screen - custom made from thousands of pentagonal-shaped Scotchlite pieces to eliminate seam lines which might show on the finished film - sits at the far end of the stage.
Therefore, in order to apply this phenomenon photographically, both projector and camera must be positioned along precisely the same axis - a physical impossibility sidestepped by the employment of a beam splitter.
Introvision International 1011 North Fuller Ave Hollywood CA was formed, expanded, and operated from 1980 to 2000 by President Tom Naud, Head Camera Production Operations Bill Mesa, and Studio Facility Builder, Set Builder and Studio Manager Issachar Issy Shabtay.