POV-Ray : Newsgroups : povray.beta-test.binaries : isosurface contained_by or evaluation problem : Re: isosurface contained_by or evaluation problem Server Time
31 Oct 2024 19:12:08 EDT (-0400)
  Re: isosurface contained_by or evaluation problem  
From: Christoph Hormann
Date: 7 Oct 2001 04:48:15
Message: <3BC017B2.DEBF4A87@gmx.de>
Mike Williams wrote:
> 
> If the solver knew where the actual surface was, then it wouldn't need
> to be told the max_gradient.
> 

I know, but it could be changed to do additional steps (meaning higher
max_gradient) if the evaluated function values differ very much from the
threshold value.  Alternatively it could also generate a warning if the
gradient is obviously higher than max_gradient and if there can't be a
visible surface with the specified max_gradient (like in this case)

> Note also that there are some functions that have regions where the
> actual gradient is infinite, but you can often get away with setting a
> smaller value for max_gradient.
> 

Although if the gradient is infinite 'across the threshold value' like
when you use a checker pattern etc. with threshold 0.5 you will most
likely not be able to totally avoid artefacts.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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