Wow, I didn't expect this much response!  Thank you to everyone who 
has responded.  OK, so basically the problem is that an Isosurface 
requires more time to calculate the effects of a ray, and radiosity 
shoots many rays, so the combination of Isosurface and Radiosity = SLOW.  
<smile>
    	Maybe I need to optimize my Isosurfaces?  I'm not sure they can be 
though, they're fairly simple; I've shown one at the end of this message.  
The other six Isosurfaces in the scene are identacle except for the 
scaling in the two functions.  Can this be optimized for speed at all?
    	Or maybe a better question; can objects be excluded from the 
radiosity calculations??  I could group these with a shadowless fill 
light if I can get them to be ignored by radiosity.
    	These rocks are part of a reef tank picture I'm trying to put 
together...  an example of the WIP is attached.


#declare Rough = function { pigment { wrinkles scale 0.75 } }
#declare Rock = function { x*x + y*y + z*z - 1 }

isosurface {
   function { Rock(x/3,y,z/2) + Rough(x+1,y+0.2,z+3.2).gray*.75 }
   contained_by{sphere{0,2}}
   threshold 0
   accuracy 0.001
   max_gradient 5.884
   texture { rockTex }
   scale 4 
   translate <0,2,-16>
} 


Thanks again for all of the responses!

-- 
Rich Allen
(Remove SPAM from my address to reply by e-mail)

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