POV-Ray : Newsgroups : povray.general : Subsurface scattering = internal radiosity? Server Time
17 Nov 2024 15:13:05 EST (-0500)
  Subsurface scattering = internal radiosity? (Message 1 to 2 of 2)  
From: Xplo Eristotle
Subject: Subsurface scattering = internal radiosity?
Date: 16 Feb 2003 04:29:00
Message: <3e4f59dc@news.povray.org>
When I got up tonight, I had a crazy idea for implementing subsurface 
scattering.

The problem with using scattering media is that it doesn't really 
"scatter" at all. If an entire object is sitting in the light, this 
isn't so much a problem, but if part of that light is blocked by 
something that casts a shadow, the shadow will completely cut off the 
scattering where it falls.

So I was thinking, would it be possible to create a system similar to 
radiosity and photons where "subsurface samples" are scattered inside an 
object or along its surface and used to light the object?

I have no idea how this would be implemented in code, so if the idea is 
any good, I'm hoping someone will take it and run with it...

-Xplo


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From: White Zebra
Subject: Re: Subsurface scattering = internal radiosity?
Date: 22 Feb 2003 13:03:06
Message: <3e57bb5a@news.povray.org>
This is actually very possible to do with Photon Mapping. The best source
for this type of implementation would be the book
"Realistic Image Synthesis Using Photon Mapping" By Henrik Wann Jensen, the
inventor of the Photon Mapping technique. There is a chapter in this book
about Subsurface Scattering.

This is not a trivial thing to implement though. Actually, there are
numerous thing the Photon Mapping technique can do well. Caustics is one of
those thing and this is already implemented in POV-Ray. Participating media
is another one which *seems* to have been implemented in POV-Ray. Global
Illumination is yet another one but the code in POV-Ray to do that have been
left in an unfinished state. And then there is no embryo of code to do the
subsurface Scatering in POV-Ray.

If anyone is willing to get their hand in Photon Mapping coding, I would
suggest finishing the Global Illumination code first.

My 0.02c

White Zebra

"Xplo Eristotle" <xpl### [at] infomagicnet> wrote in message
news:3e4f59dc@news.povray.org...
> When I got up tonight, I had a crazy idea for implementing subsurface
> scattering.
>
> The problem with using scattering media is that it doesn't really
> "scatter" at all. If an entire object is sitting in the light, this
> isn't so much a problem, but if part of that light is blocked by
> something that casts a shadow, the shadow will completely cut off the
> scattering where it falls.
>
> So I was thinking, would it be possible to create a system similar to
> radiosity and photons where "subsurface samples" are scattered inside an
> object or along its surface and used to light the object?
>
> I have no idea how this would be implemented in code, so if the idea is
> any good, I'm hoping someone will take it and run with it...
>
> -Xplo
>


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