On 5 Sep 2001 23:52:35 -0400, Michael Davis wrote:
>ron### [at] povrayorg (Ron Parker) wrote in
><slr### [at] fwicom>: 
>
>>On 5 Sep 2001 21:18:22 -0400, Michael Davis wrote:
>>>First, I'm seeing some sort of corruption on an object using the
>>>crackle pattern for both the pigment and normal aspects of the
>>>texture.  Specifically, there are lots of horizontal streaks
>>>running across the surface of the object in one area of it.  I
>>>haven't seen anything like this rendering the same scene under
>>>either version 3.1g or MegaPov 0.7 (also for Windows). 
>>
>>Any chance you can provide a scene file that shows just this
>>effect without all of the other stuff?
>
>Try this one.  It has the same object, and the camera's been moved a 
>bit closer, so you should be able to see it better (assuming it isn't 
>just a problem on my system).  The effect should be visible in the 
>middle portion of the image.
>
>I've played with it a bit more on my own and discovered that the 
>problem goes away if you remove Piece1 (the union of 7 tori) from the 
>scene, and still seems to appear (although it's harder to see) if 
>Piece1 is the only thing in the scene.

Thanks, that was enough to track it down.  For those who are playing along
at home, the crackle pattern keeps a cache of what the pattern looks like
near the most-recently-sampled point, and if the next point is nearby it
uses the cache instead of recalculating the values for every point.  In
the case of #declared crackle pigments and normals, however, the cache
was inadvertently being shared between all instantiations of the #declared
pattern.  

This has been fixed in the development version; the fix should appear in 
a future beta version.  Thanks very much for the report.

-- 
#local R=<7084844682857967,0787982,826975826580>;#macro L(P)concat(#while(P)chr(
mod(P,100)),#local P=P/100;#end"")#end background{rgb 1}text{ttf L(R.x)L(R.y)0,0
translate<-.8,0,-1>}text{ttf L(R.x)L(R.z)0,0translate<-1.6,-.75,-1>}sphere{z/9e3
4/26/2001finish{reflection 1}}//ron.parker@povray.org My opinions, nobody else's

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