> Off work today and playing with Sam's Tovolume code when it hit me, what
> he has discovered is an incredibly easy way to create silhouette based
> isosurface shapes.
>
> The blur.png file was drawn freehand in gimp with a solid brush after
> which a Gaussian blur was applied - the blur is what Sam's proximity
> pattern is doing in Tovolume. This single image is then used to create
> the isosurfaces with the following code:
>

> #declare Iso00 = isosurface {
>      function { Fnct03(x,y,z) }
>      contained_by { box { <-0.68,0.02,-0.68>,<0.68,0.98,0.68> } }
>      threshold 0.00
>      accuracy  0.001
>      max_gradient 160.00
>      max_trace 1
>      pigment { color Magenta }
> }


I have'nt tryed the third version, but I got very good renders, much 
faster after some little changes to your code.

First, max_gradient 160 if huge overkill.
Using max_gradient 1.5 resulted in a nice render without any message 
about max_gradient been to small or to large.
Next, I used:
#declare MinFact = 0.6;
evaluate 1.5*MinFact, sqrt(1/MinFact), 0.7
and got a slightly faster render.

Next, I reduced the contained_by object as follow:
box {<-0.34,0.02,-0.34><0.34,0.908,0.34> }

It's now much tighter and large enough to contain the whole isosurface. 
This got me another performance increase.



Alain

Post a reply to this message