T3D Re: TECH-3D digest 544

[Steve Madsen <steve@xxxxxxxxx>]

>
>>A friend of mine has done some incredibly detailed computer artwork of
> the
>>Blade Runner Spinner-- the car looks almost real. He can even make the
> car
>>do a fly-by with perspective changes. He's willing to try to do the
>>manipulation that will create a stereo pair-- can anyone point me to
> sites
>>where the process involved is explained?
>
> Simply have him render a frame, then offset the camera by 2.5 inches
> horizontally in object space, then render again.
>
>      -Greg W. (gjw@xxxxxxxxxx)

Of course, since scale is arbitrary in 3D models
(300m tall refrigerators often result when 
translating between 3D file formats), what you 
really want to do is move camera horizontally 
by 1/50th the distance to nearest object in scene;
this rule will get you close to what you want
regardless of the actual scale of the scene to
be rendered, then just iterate a bit to achieve the
"right" parallax (eg if near object is 50m from
camera then start with a camera shift of 1m; if
near object is 10cm from camera, initial camera
shift would be 2mm).

(The great thing about 3D modelling packages is
that measuring the distance from camera to
near object in scene is a snap!)

If all you want is a stereopair for freeviewing,
then the two images placed side by side is all
you need.  If you want to use LCD shutter glasses
or make an anaglyph, some additional processing 
(and likely some commercial software) will obviously
be necessary.


Steve Madsen