Red/Cyan stereo in Geomview

["A.Daviel" <advax at erich.triumf.ca>]

I obtained a copy of the Geomview binary for the SGI via ftp for evaluation
(well, to be honest, playing with. I have an application to use it in
conjunction with some FEM to model submarine pressure hulls, but it is
outside my area of expertise and as a hobby project may come to nothing. BTW,
If you know of any public domain FEM package, I would be most interested, as
I was thinking of writing something rather crude myself). 

I was experimenting with the stereo capability in Geomview. I made some 
red/blue glasses, but had problems with the Cyan display. If I selected edges 
only and viewed one of the simple polyhedra in stereo, I would see only one 
image through the red lens. But I was unable to adjust the colour of the 
edges so that I could see only one image through the blue lens. It seems to 
me that as the display is in fact composed of three coloured phosphors, and 
makes other colours by addition, that one could only obtain distinct images 
if the left and right images activated only one phosphor, and my lenses 
passed only light from the corresponding phosphor. This would suggest that
the two images should be in a pair of the primary phosphor colours, red,
green or blue, rather than using cyan which the display shows as a mixture of
blue and red. 

I was also having trouble using the stereo viewing angle slider. It may be 
that I have not properly understood its use, but it seemed to affect the 
camaera psotition in a non-reversible way (if I moved the slider to the left, 
then back to the original position, the viewed image did not return to the 
original state).

Andrew Daviel <advax at triumf.ca>