Am 15.04.2013 23:46, schrieb Alain:

> The double nearest_count can affect the quality and the speed. The first
> value set the maximum bound to be used in areas where the samples have
> more variation. The second value is the minimal value to be used in
> areas where everything is prety uniform, like a large, plain wall.

No, not exactly.

Normally, during pretrace the whole image is scanned over and over again 
with ever increasing resolution, as specified by the pretrace_start and 
pretrace_end parameters. In each pass, for each individual location 
probed it is checked whether the nearest_count condition is satisfied, 
and if not, another sample is added there.

This is rather inefficient, as in regions where the individual locations 
probed already did satisfy the nearest_count location, it is unlikely to 
find individual locations that don't satisfy that condition yet.

If you specify a second parameter to nearest_count, regions where the 
/average/ sample density satisfies this second condition in one pass are 
skipped in any further pretrace passes.


Thus, the second parameter to nearest_count can be considered an average 
sample density to aim for, while the first parameter can be considered a 
local maximum sample density.

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