POV-Ray : Newsgroups : povray.general : Using a function in a height_field declaration : Re: Using a function in a height_field declaration Server Time
15 Jul 2024 15:00:54 EDT (-0400)
  Re: Using a function in a height_field declaration  
From: Bald Eagle
Date: 14 Feb 2023 18:30:00
Message: <web.63ec196943a1dd881f9dae3025979125@news.povray.org>
"Kenneth" <kdw### [at] gmailcom> wrote:
> "Kenneth" <kdw### [at] gmailcom> wrote:
> >
> > If you mean that the 'center' of the sine wave circle is
> > not 'at the origin' but at z=1 instead, that could be due to a long-standing
> > problem with how functions are kind of mirror-reversed when used in a
> > height_field...
>
> BTW: That old problem had strange effects: no only of the z effect of the
> function being reversed to '-z', but also x to -x. It was -- is? --a
> 'double-reversal' mirror effect...with the 'origin' of the function moved to
> z=1, not at <0,0,0>.
>
> I thought for sure that this had been corrected, but I have not played around
> lately with such height_fields to see.

You might have to play around with this a bit more - but the issue that you may
be seeing is that height_fields are by default "made" in the region <0, 0, 0> to
<1, height, 1>.

Just like an image_map is a unit square.

So usually one just translates it -0.5*(x+z) and it then centered at the origin.

But am definitely seeing a difference in my isosurface vs height_field, so
thanks for this little question - I will see if that's part of the issue with my
scene as well.

- BW


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