Fab wrote:
>>If you want the cylinder to fill your whole image the radius
>>has to be the same as the distance to the camera if the camera angle is
>>90 degree.  If your radius is 250 and the distance from the camera 500
>>(it's only 499 in your sample) the cylinder fills half the width of the
>>image.
> 
> 
> ok. but it is exactly what I do not understand.
> 
> in optic, if the radius is 250, the cylinder should NOT fills half the width
> of the image.
> 
> if I wished to fill half of the image, I need a radius of   tan ( 90 / 4 ) *
> 499
> and that's not the case with povray.
> 
> And my question is : Why isn'it like in optic with povray ?

POV-Ray is completely correct here.  Just draw it on a piece of paper 
and you will see.

Christoph

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Last updated 25 Oct. 2003 _____./\/^>_*_<^\/\.______

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