POV-Ray : Newsgroups : povray.binaries.images : 'solid media' human model : 'solid media' human model Server Time
28 May 2022 12:51:19 EDT (-0400)
  'solid media' human model  
From: Kenneth
Date: 14 Apr 2022 09:20:00
Message: <web.62581d6d2bcfb4164cef624e6e066e29@news.povray.org>
I'm a big fan of rendering 'solid media' objects-- that is, using the object
*as* the media container, then filling it with media so dense that it 'looks'
solid. Depending on the density pattern used, this can produce some
complex-looking objects.

While experimenting with some related stuff, I came up with this simple example.
It's an *old* pure-CSG model that I constructed years ago (and that I tweak from
time to time.) It's made of spheres, cylinders, cones, and superellipsoids, and
is about 1.5-units tall. For such CSG objects, the media result looks *much*
better and more solid when all of the parts are 'merged' together (rather than
as simple unions), and renders faster as well.

These were my media settings:

object{ MY_OBJECT
hollow
texture{pigment{rgbt 1}}
interior{
 media{
 scattering{1, 300 extinction 0.7}
 method 3
 intervals 1
 samples 47, 139
 aa_level 4
               density{
               bozo scale .055 sine_wave frequency 4// Interestingly, the
// ordering of sine_wave and frequency makes a difference-- the visual result
// is different when reversed.
               color_map{[.6 rgb 0][.6 rgb 1]}
                      }
        }
         ...

The samples min,max values are interesting: From tests, I decided to make the
min value about 1/3rd of max. It saves a lot of rendering time, and the media
result looks almost as good as when using the higher value for both min and max.
That's debatable, of course ;-) I probably should have used a 1:2 ratio.

I used two light sources-- one as a 'fill' light, because the shadowed parts of
the media are very dark due to the density.

There are some bright light-streak errors in the upper part of the model; they
are due to the main light_source shooting it rays through what are apparently
some gaps in the model's parts-- and due to all of the parts being merged
together. (The steaks do not appear when the model is made of unions instead.) I
need to find where those gaps are!


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