Some computer programs for producing stereoscopic pairs obtain the left and right projections by rotating the object about its axis to provide the necessary visual parallax. Although the method may be expedient, the resulting image is distorted, because the two projections are always placed in the same plane for viewing. Numerical and graphical examples are given to show the degree of distortion of the image when the pair is viewed through a stereoscope or projected on a screen.
Bernard G. Saunders, "Stereoscopic Drawing by Computer—Is It Orthoscopic?," Appl. Opt. 7, 1499-1504 (1968)