Remco de Korte schrieb in Nachricht <3A79D232.8C7C423C@xs4all.nl>...

>Thanks for the hint. I didn't think it would matter much but I expect if
you
>think about it would.

Well if I understand it right, the function must be calculated for every ray
hitting the container object. Okay, there may be (no, there are) some cache
strategies, but if you make a picture which is only partly occupied by a
isosurface you can see that rendering slows down, when it comes to the
container. Since you don't need the empty parts of the container, it's only
wasted time.

> I was already worried about the speed.

I did not try it myself but maybe it would help to precompute some more
constant terms in your final function. If you precompute things like w*pi/ph
or add  #declare f1 = f1*pi/ph, less has to be computed at rendertime. I
might be wrong with this but I don't think that POV really recognizes those
constant terms in the function (but I would be glad if someone would tell me
that I'm wrong).
As far as I can see, the '1+' for the sin and cos part is not nessecary too,
because it only levitates the Iso a bit. It would be intresting to test if a
translated Iso with a simpler function is faster than a more difficult one,
which is at the right place allready. I bet it is.

OTOH all this will not make that much difference IMHO, and there were some
rumours that Isos will be 10 times faster in the next official version.
Hopefully who ever is working on that is succesfull!

BTW: What are the rendertimes for this? How long took one frame?

Marc-Hendrik

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