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. In order to
do so, I combine

(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.

My camera view is from above, simulating a satellite view (Z-direction is "up")
and assuming a simple planar object in xy. While the above-mentioned method
works in most cases, it seems that for large coordinates (e.g. 1 000 000
translation of both camera and luminaire in the xy plane), it no longer does (it
becomes a regular point source), and some black dots appear in the resulting
image. The strange thing is that it is not the case for translations of, e.g.,
100 000.

Has anyone encountered similar problems and/or knows the reason for this?

Jasper

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