I am working on a scene where I want a small trail of steam.  But just using
a scattering media doesn't give enough substance to it.  I do slightly
better (loosing a bit of realism perhaps) by turning on emission and
absorption.  But it's still not enough.  The only knob I know to adjust for
the density of the media is the color, with black being no density and
white being some maximum.  I would like to be able to adjust the maximum.
Is there some media parameter such as mean_free_path or penetration_depth
that I'm not aware of?  The only thing I can figure out is to scale my
entire scene by some large factor, but I was hoping it wouldn't come to
that (a lot of work).

fade_distance and fade_power are tantalizingly close, but when I adjust
these it simply darkens the entire interior.

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> The only knob I know to adjust for
> the density of the media is the color, with black being no density and
> white being some maximum.

There is no maximum color. Anywhere a color is expected, you could use
something like <10000,10000,10000>.

My general approach to media density is to take the base color I want and
multiply it by a scalar to tweak the density: <1,.5,.25>*3

One thing you can try for some artistic freedom is to use extinction 0, so
you only get the brightening effect that scattering media has, and then add
absorption on top of that. This lets you control the absorption and
"reflection" colors separately.

 - Slime
 [ http://www.slimeland.com/ ]

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Speaking of fog, I keep getting a message that my scene camera is in a
non-hollow object and therefore fog and other media insertions will not
appear correctly. I've looked through the documentation and help files, but
can't seem to actually find a script that can be used as a work around. I'd
like to know how I can introduce a script -- and where it needs to be
inserted -- that will change my camera to being in a hollow object so that
fog will appear. I am exporting a scene from Chief Architect Version 10.06a,
and I would therefore suppose that the camera is located in Chief also. I
have
no way in the Chief program to adjust the camera, so am hoping there is a
fix available in POV.

Thanks, Dan the newbie
Windows XP Pro
POVRay Version 3.6.1a
AMD 4800-X2 oc to 2.62Ghz
Seagate dual mirrored 250GB
2x BFG 7800 GTX oc. in SLI
2 GB PC3200 DDR

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DL Drafting nous apporta ses lumieres en ce 2005-11-18 18:52:
> 
> Speaking of fog, I keep getting a message that my scene camera is in a
> non-hollow object and therefore fog and other media insertions will not
> appear correctly. I've looked through the documentation and help files, but
> can't seem to actually find a script that can be used as a work around. I'd
> like to know how I can introduce a script -- and where it needs to be
> inserted -- that will change my camera to being in a hollow object so that
> fog will appear. I am exporting a scene from Chief Architect Version 10.06a,
> and I would therefore suppose that the camera is located in Chief also. I
> have
> no way in the Chief program to adjust the camera, so am hoping there is a
> fix available in POV.
> 
> Thanks, Dan the newbie
> Windows XP Pro
> POVRay Version 3.6.1a
> AMD 4800-X2 oc to 2.62Ghz
> Seagate dual mirrored 250GB
> 2x BFG 7800 GTX oc. in SLI
> 2 GB PC3200 DDR
> 
> 
> 
> 
> 
> 
> 
Try to identify the object in whitch the camera is located and add hollow to it's
definition. It may 
be a plane, a large sphere used for the sky or some other object. If the camera is
inside a room, 
that room may be a box like object, make it hollow.
hollow don't affect the apearence of the object nor the way it interact with other
objects in thwe 
scene. What it DOES affect is the way it interact with fog and medias. Those can have
an effect 
inside an hollow object.

-- 
Alain
-------------------------------------------------
Everybody should believe in something: I believe I'll have another drink.

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