Le 19-05-13 à 07:29, Jasper a écrit :
> Hello everyone!
> 
> I am trying to introduce photometric data files of luminaires (i.e. IESNA .ies
> or EULUMDAT .ldt) in Povray to get "correct" lighting distributions. This
> currently works by combining
> 
> (1) a point light source
> (2) a sphere with radius 0.01 and spherical mapping of an image map (.png with
> the alpha channel used for transparency) which represents the lighting
> distribution for different angles.
> 
> However, for large coordinates (e.g. 1e+6), I get unwanted black spots in a
> regular pattern (see attached image on the left).
> 
> Jasper
> 

You may try using a larger sphere when the scale of the scene get larger 
than about 1e+4. It may reduce the rounding errors to some extent.

The best thing to do is to limit the size of the scene to be less than 
1e+5 if at all possible.

Build your scene around the origin. Don't be afraid of negative numbers.

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