P3D Re Stereo Laser Pointers

[Peter Homer <P.J.Homer@xxxxxxxxxxxxx>]

As Bob Maxey pointed out it is not clear what the original poster on this
subject was trying to do. Produce a pointer that is visible in both eyes in
stereo projection. Which should be possible with an unpolarised pointer or
a polarised fitted with a 1/4 wave plate to convert to circular
polarisation as already suggested. Or produce a pointer that can move in
and out of the stereo scene. The reference to red ang green pointers
suggested to me that they were thinking along these lines but for anaglyph
projection. While it should be possible to use polarised pointers in
polarised projection and I have seen an article in the French stereoscopic
society bulletin describing this. The language barrier is a problem but as
far as I can tell it uses two polarised pointers mounted together on a gun
like device which holds them at the opposite 45 degree angles. The trigger
of the gun is squeezed to alter their seperation against a spring which
returns them to the original position.
  Another way to point stereoscopicaly is to use something like a pencil
just in front of the lenses . There are two shadows produced but with the
glasses on just one is seen by each eye producing a stereo shadow ,moving
the pencil back and forth causes the shadow to move in and out of the
screen.  P.J.Homer



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