Sam Van Oort wrote:
 > Stereo ptch is VERY useful.  One question though: what are "Good"
 > stereo_base value for normal eyes?
 >
 > I can't seem to get it to "pop out" when I set the values.
 >
 >

Thank you, I am allways glad if it's usfull for someone :-)

Meanwhile it showed up, that the handling of the stereo window can
be confusing for some scenes/camera setups. There were some threads
on povray.general:
"How can I shift the image plane?"
"Scenes and rendered images of this problem"
"Stereoscopy"


To sumarize it:
I defined the stereoscopic camera in StereoPOV in a way it produces
a sort of "natural window" located in the image plane. So all objects
*behind* the image plane will be behind the screen, regardless of the
setting of the stereo_base.
Now this happens to be confusing, if the size of the camera is not
related to the size of the objects in the scene. This often is the
case, because in "normal" (mono, 2D) mode this whole issue is
irrelevant; so e.g. with some of the example scenes of POV-Ray you may
run into problems.
I myself didn't notice this problems, because I have the habit to
rather use real world units in my scenes.
So in the next release (based on 3.5 code, after the official final
release of 3.5 will be out), I plan to introduce a sort of
"convienience shortcut" to adjust the distance to the stereo window.


For now, consider the following example:


------------------------------------------------------------

camera{
   location 0
   direction z
   up y
   right 4/3*x
   stereo_base -0.065
   }

light_source{<-2,3,-2>
              colour rgb 1
             }

plane {y, -0.5
   texture{
      pigment{checker
             color red 1 green 1 blue 1
             color red 0 green 1 blue 0
      }
   }
}


sphere{ 0.8*z 0.3
   texture{pigment{colour rgb 0.8}}}
------------------------------------------------------

The image plane is defined by the camera location and direction.
Hence, because the stereoscopic window is in the plane, the window
will be at <0,0,1> and will be 1 Unit high and 1.33 Units wide.
Because the sphere is nearer than this window, it will show up
"off screen", i.e. "plop up" before the window.

(Btw: I used a negative stereo_base for cross eyed view)


Here, I used units oriented at real world units (1 Unit=1m)
But it is not required to do so.
I you are unshure how to choose the stereo_base, try 1/30 of
the distance to the nearest/main object as a starting point.
(the so called "1:30 Rule")


Hope, this helps.
Please tell me, if it was confusing, or
if you need further help with setting up the camera.

Regards,
Hermann Vosseler

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