hello group!

has anyone had success simulating realistic volume scattering objects, like
teeth? i know a lot of work has gone into rendering realistic skin, which is
also a volume scatterer (google BSSRDF) ... but is it possible with povray?

i experimented with scattering and absorbing media, for example with the
following material:

material {
    texture { pigment {rgbt <1,1,0.9,0.1> } }
    interior {
      media {
         scattering {1, rgb <0.8,0.6,0.2>*10 extinction 0.01 }
      }
   }
}

when i turn up the pigment transparency i get a fog-like object, when i set it
low you cannot see the inside. the effect is far from satisfactory. can anyone
please give me a hint?

thanks a lot
christoph

Post a reply to this message

"Christoph" <nomail@nomail> wrote:
> has anyone had success simulating realistic volume scattering objects, like
> teeth? i know a lot of work has gone into rendering realistic skin, which is
> also a volume scatterer (google BSSRDF) ...

Actually, AFAIK all materials except metals are volume scatterers to some
degree...

> but is it possible with povray?

Do you mean "possible" or "feasible"? ;P

> i experimented with scattering and absorbing media, for example with the
> following material:
>
> material {
>     texture { pigment {rgbt <1,1,0.9,0.1> } }
>     interior {
>       media {
>          scattering {1, rgb <0.8,0.6,0.2>*10 extinction 0.01 }
>       }
>    }
> }
>
> when i turn up the pigment transparency i get a fog-like object, when i set it
> low you cannot see the inside. the effect is far from satisfactory. can anyone
> please give me a hint?

Yes: Crank up the pigment transparency, but also the media density. *10 is still
*WAY* too low for any good effect.

Plans exist to add some dedicated subsurface scattering mechanism to POV, but at
the moment they're no more than plans and a bit of feasibility study code.

Post a reply to this message

"Christoph" <nomail@nomail> wrote:
> has anyone had success simulating realistic volume scattering objects, like
> teeth? i know a lot of work has gone into rendering realistic skin, which is
> also a volume scatterer (google BSSRDF) ... but is it possible with povray?

Scattering media is the best approach, for the most part, but it is not
optimized for the effect.  It is also possible to fake it with some clever
tricks.  It is also possible to use the montecarlo method with mc-pov, but I am
not aware that this patch has actually been integrated into mc-pov.  Here's all
of the references I can find:



Kari Kivisalo's approach to media subsurface scattering:
http://news.povray.org/povray.binaries.images/message/%3C3B97ABD4.5E70568D%40engineer.com%3E/#%3C3B97ABD4.5E70568D%40en
gineer.com%3E

http://news.povray.org/povray.binaries.scene-files/thread/%3C3B97C908.42BE1B68%40engineer.com%3E/



Some of my tests with media:
http://news.povray.org/povray.binaries.images/thread/%3Cweb.47b1299720742c82ae42298f0%40news.povray.org%3E/?ttop=302088
&toff=550

http://news.povray.org/povray.binaries.images/thread/%3Cweb.47249824ccd73a9188727a860%40news.povray.org%3E/?ttop=302088
&toff=750

http://news.povray.org/povray.text.scene-files/thread/%3Cweb.4726c3e669db4c2888727a860%40news.povray.org%3E/




Samual Benge's proximity macros for faked subsurface-scattering:
http://news.povray.org/povray.binaries.scene-files/thread/%3C489f4610%40news.povray.org%3E/

http://news.povray.org/povray.binaries.images/thread/%3C489f82c0%40news.povray.org%3E/?ttop=302088&toff=250

http://news.povray.org/povray.binaries.images/thread/%3C489f4818%40news.povray.org%3E/?ttop=302088&toff=250

http://news.povray.org/povray.binaries.images/thread/%3C489bc01b%40news.povray.org%3E/?ttop=302088&toff=250




Fidos' montecarlo technique:
http://news.povray.org/povray.binaries.images/thread/%3Cweb.4838403f151ae76dd309f1e00%40news.povray.org%3E/?ttop=302088
&toff=400


Out of all of those, some options should present themselves, but it would be
nice if these techniques could be formalized so you didn't always have to go
searching and start by mangling someone else's scene...

 - Ricky

Post a reply to this message

"triple_r" <nomail@nomail> wrote:

> Here's all of the references I can find:

Thanks for gathering all of these links into one place; it makes a good
'reference page.'

KW

Post a reply to this message

thank you very much! seems like i had the wrong search term ... but this looks
all very good.

Post a reply to this message