In article <3a0c5d3a$1@news.povray.org>, Ken Cecka <cec### [at] homecom> 
wrote:

> Using noise3d, the shifts between rows tend to form up in patterns, 
> gradually shifting one direction, then back the other.  I'd rather have 
> those shifts be completely random. 

Perhaps you would have better luck with a pigment function...crackle, or 
granite...


> Based on Chris Huff's explanation, it sounds like rand() won't do 
> this for me since it will only be calculated onec for the whole 
> function. 

Not quite. You currently have to declare a value outside the function 
and use it, so doing that will calculate it once. If rand() ever becomes 
available inside functions, it will be calculated every time the 
function is evaluated, which will make it useless for isosurfaces. 
(though still useful for patterns, to give a "grainy" effect)


> So I'll have to play with exagerating the shifts produced by 
> noise3d(), or come up with some other pseudo-random effect that I can 
> generate on my own.

Try only evaluating noise3d() at certain points, and scale it very small 
so the "patterns" are smaller than the rocks.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

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