> this is a problem I've suffered from too. For some
> extreme examples (and some hints) see in povray.general:
> 
>    Intersection with quartic: bug?   3 Sep. 2002
>    Small is NOT BEAUTIFUL           11 Feb. 2003
> 
> The reason for this behavior are some 'Epsilon' values in the
> Pov-Ray code which are neccessary (in this way some overlap is
> created at corners to make them 'watertight', without such overlap
> it would  sometimes be possible to look inside objects at corners
> due to limited numerical precision), but these 'Epsilons' are a
> little large.

Thanks for the info. I actually tried and multiplied everything in my 
secene by 100 so that the smalles dimension is now about 0.5 units and 
largest is about 600 units and it looks like all the artifacts 
disappeared. I also noticed some very slight changes with radiosity but 
I believe the result is now more accurate.

In my opinion this is something that should be mentioned in the 
documents (if it is: good, then forget this) - if any rule of thumb can 
be given in this matter. People might spend too much time searching 
coincident surfaces when the problem is somewhere else.

Severi Salminen

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