Kenneth nous apporta ses lumieres en ce 2005-10-18 16:43:
> I've discovered some odd anomolies when trying to scale several of POV's
> built-in PATTERNS (when used in a PIGMENT block).  Not a bug, really, just
> undocumented(?) behavior.
> 
> There are visual differences between scaling a pattern using the recommended
> FREQUENCY modifier vs. the more generic SCALE modifier.   The FREQUENCY
> modifier seems to actually alter the pattern itself, whereas SCALE does
> not.  I.e., SCALE preserves the visual pattern and simply makes it larger
> or smaller, as would be expected. FREQUENCY, however, creates a kind of
> subtle "banding" in addition to scaling (the banding looking similar to a
> perturbed WOOD pattern.)
> 
> The patterns that show this are GRANITE, AGATE and BOZO (which leads me to
> believe that this anomoly only shows itself in patterns which use "noise"
> as a generator, and/or TURBULENCE.)
> 
> I realize there may be reasons for this behavior, perhaps in how the
> patterns are generated.  But practically speaking, I prefer to use SCALE to
> alter their size, as the pattern appearance is preserved.
> 
> However.... this is not a cure-all for the problem in general.  SCALE does
> not seem to work at all on the RADIAL pattern, wheras FREQUENCY does.  And
> conversely, FREQUENCY doesn't work on the CELLS pattern, while SCALE does!
> 
> Perhaps a few caveats could be inserted in POV's discussion of FREQUENCY, to
> alert users to this behavior?
> 
> Ken
> 
> 
> 
Scale alters the size of the pattern. It can have different values for all 3 axis.
Frequency alters the COLOR_MAP used, making it repeat itself several times as the
pattern's value 
goes from 0 to 1.

-- 
Alain
-------------------------------------------------
Jehovah's Witnesses #3: Shit has been prophesied and is imminent; only the righteous
shall survive 
its happening.

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