Alain <aze### [at] qwertyorg> wrote:

>
> > camera {
> >
> >      #declare xS = 0;
> >      #declare yS = 1;
> >      #declare zS = 0;
> >      up<xS,yS,zS>
> >      right x*image_width/image_height
> >
> >      angle 1
> >      location<0,0,-2000>
> >      look_at (Position - 9*x)
> > }
> > .....
> > light_source {                    // far enough to avoid problems ...
> >    0
> >    color White
> >    translate<20000, 30000, -10000>
> > }
> >
> > For zCam<= -1958.5 or zCam>= 2003.5, all the defects in my scene (where there
> > are other SORs, affected by the same problem) are gone.
> >
> > Gilles
> >
> >
> >
> >
> >
> >
>
> You place your camera at a large distance and use a very small angle
> that effectivelt removes perspective. That, in turn, can cause
> calculation errors. Those errors will cause the apearance of various
> artefacts.
>
> Try placing your camera closer and use the orthographic projection. It
> effectively simulate a camera set at infinity.
>
>
> Alain


I can imagine that (this is also a reply to Warp) floating point has a limiting
accuracy, which may be critical when you deal with infinitely thin (right ?)
surfaces like SOR.
Of course, without looking at the algorithm, one cannot say more ...
I am nevertheless slightly amazed by the fact that the defect vanish when you
move the camera closer or FARTHER from the object ...

Gilles

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