In article <3a1e6b2a@news.povray.org>, "Wlodzimierz ABX Skiba" 
<abx### [at] abxartpl> wrote:

> first I prepare CSG than I declare function{pigment{object{...}}} to 
> describe interior of it and then I clone this as isosurface. 
> Isosurface has artifacts even with accuracy 0.00005.
> I have calculated value (with eval) of max_gradient as 200000 but this
> not help.

The object pattern has two states: on and off. It doesn't have any 
"in-between" values. Patterns like this have an infinite gradient, and 
cause the isosurface algorithm problems. Other patterns that have this 
problem are checkers, hexagon, brick, and any pigment that has sharp 
lines. Warp is using the boxed pattern, which does vary smoothly, but 
his color_map is [0 rgb 1][0 rgb 0][1 rgb 0], which looks like a mistake 
to me...it is completely black, with no variation at all, basically a 
big, slow rendering 0. I think he wants [0 rgb 1][1 rgb 0] instead.

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

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