POV-Ray : Newsgroups : povray.general : planet atmospheres: emission good, scattering bad Server Time
9 Aug 2024 15:17:36 EDT (-0400)
  planet atmospheres: emission good, scattering bad (Message 1 to 2 of 2)  
From: ryan constantine
Subject: planet atmospheres: emission good, scattering bad
Date: 12 Jul 2000 01:17:16
Message: <396BFF08.3886624@yahoo.com>
after waiting eternities for scattering media to render with area lights
on large pics, i decided to try using emitting media for planet
atmosphers instead.  of course, the main problem with emitting media is
that it will be lit on the darkside of the planet as well as the light
side as is evidenced by my first planet posts some weeks ago.  at that
time, i was pointed in the direction of some very good tutorials using
scattering and absorbing media together for the right effect.  this
gives very good results at phenomenal render times.  some of you may
have noticed that rendering an image at resolutions up to 800 by 600
gives good results if shown on screen, but when printed out, leave much
to be desired.  the problem is with the pixels per inch and the solution
is rendering absolutely huge images (over 2500 pixels wide).  not a
problem if you render the standard ball on a sphere, but when scattering
media comes into play, well, i'm sure you know what happens.  and you
can forget about throwing radiosity into the mix.  then i was re-reading
the pov docs and came across multiple densities.  this time i thought of
a use for it.  the result was simple and renders fast.  emitting media
is done in a spherical density combined with a gradient density color
map. the gradient is scaled at twice in its direction and translated the
radius of the circle taking care that everything is oriented so the
light source (the sun) is on the side with the media.  for more
information, check my scene post in the appropriate ng.


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From: Tony[B]
Subject: Re: planet atmospheres: emission good, scattering bad
Date: 12 Jul 2000 08:58:16
Message: <396c6b68@news.povray.org>
You could also use planar instead of the gradient.


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