In article <37391633.0@news.povray.org> , "Rainer Minixhofer" 
<min### [at] sboxtu-grazacat> wrote:

> I'm using POV-Ray v. 3.1d.msvc.win32 [Pentium II optimized] with an
> AMD-K6-3D 350 Mhz and an Asus P5-B AT Motherboard and fairly
> enought Memory (192 MBytes).
>
> Following POV-Ray commands cause a simple sphere to be some-
> how clipped around it's border:
>
>
>
> #declare cameraorig=< 0,0,0>;
> #declare cameratarget=< 740000000,-19000000, 130000000>;
> #declare camerapos=cameratarget+vnormalize(cameraorig-cameratarget)*50;
> camera{
>   location camerapos
>   look_at cameratarget
> }
> light_source
> {
>   0
>   color rgb <1,1,1>
>   looks_like {sphere {0, 700000}}
> }
> sphere {0, 18
>         texture {
>             pigment {color <0.8,0.8,0.8>}
>         }
>         translate < 740000000,-19000000, 130000000>
>        }
> sphere {0, 20
>         translate < 750000000,-13000000, 100000000>}
>
> It's clear that the size of the spheres and their position in space cover
> several order of magnitudes.
> So maybe this problem is somehow related to internal precision of variables.
> But if one inserts
> the keyword orthographic in the camera section, the sphere renders fine. One
> can also try to
> remove the second sphere and the problem will disappear (this is also the
> fact if one removes
> the looks_like statement in the light-source section).
> Overall this is a very strange behaviour and it looks like a bug inside
> POV-Ray.


No, inside your scene: You values are to large and go outside the limits of
precision. Simply write 74000.0000,-1900.0000, 13000.0000 etc and there
won't be any problems - anyway, maybe a wraning about these limits wouldn't
be such a bad idea...



     Thorsten

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