On Mon, 29 Jul 2002 00:32:08 -0500, Richard Morehouse
<rmo### [at] coxnet> wrote:

>can anyone help?

You've taken a lightly wrong path, Richard. Not that it won't get you
where you want, it's just that you'll get there *very* slow.

Before you go on reading, please revise the radiosity section in the
manual, especially "always_sample", "save_file" and "load_file".

Now, if you want to have realistic render times with radiosity and
reflection or refraction, there is a trick most people do. Basically
the idea is to calculate radiosity first, then render
reflection/refraction. This is done in two steps. First, remove all
reflection, transparency and refraction from your objects, and render
the scene with:

always_sample on 
save_file "radiosity_file.dat"

This will calculate the radiosity contribution of all objects,
including reflective and refractive ones, without going through the
pain of including reflection and refraction in the render times. As a
bonus, this render can be done using lower image resolution settings
(no anti-aliasing and half the height and width).

Then, on the second stage, bring back your transparency, refraction
and reflection and use these settings:

always_sample off 
load_file "radiosity_file.dat" 
preview_start 1 preview_end 1

This will load the radiosity data already calculated and will not
calculate any more radiosity samples, which is the idea (it is very
slow with reflection and refraction). Render at normal resolution,
anti-aliasing and all.

This same trick is also applicable when you want to continue a trace
with radiosity - save the radiosity date in the first stage, then
start the real render using the second settings - you can continue
that render as often as you want to.

If I got anything wrong, someone please correct me before Richard
starts another month-long render..

Good luck!


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

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