Hi folks,
I'm back with some new things to share.

1 - Mixed sss and aoi (mlpov0.83/megapov1.1) : not too bad, I think it's ok.
Aoi is quite helpful, especially when an image map is used as last layer
(the white edge is usually lost).
Script posted in p.b.s-f.

2 - As anyone knows, a serious problem with making sss human skin in pov is
transparency tuning, particularly with head due to its structure (inner
parts).
- I always read here (in the newsgroup) that we just have to increase media
density to turn it more opaque. Well, I noticed it's true only when main
light is from behind. But when main light is in front, I discovered that it
is absolutely the opposite, we have to *decrease* this value (?!)...
- extinction is useful when tweaking
- big time-consumer, high value sampling is used as last resort if density
and extinction are not sufficient.

Some examples here using scattering type 1 in different lighting situations:
Because human skin is one of the most subtle and inconstant material, it is
not a straight method (I'm not capable to do one !), just to refer as memo.

http://bambousette.free.fr/head_experiment/povsss+lightBackgrd.jpg
http://bambousette.free.fr/head_experiment/povsss+lightFB.jpg
http://bambousette.free.fr/head_experiment/povsss+lightForegrd.jpg
http://bambousette.free.fr/head_experiment/povsss+lightSide.jpg

3 - I've also tried with non-sss technics, not convincing at all (except
aoi).

http://bambousette.free.fr/head_experiment/non-sss_skintest.jpg

4 - I've tried with other 'things', but unsuccessfully.
[ Jaime : I've tested your 3d cafe skull idea, but unfortunately does'nt
work here. I don't know how you really did it. Probably you are very
inspired. Jaime, ...are you a sort of wizard ? lol ]

http://bambousette.free.fr/head_experiment/other_sssexperiment.jpg


Rene
----

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Toying with Globulous (a model by Jan Hofmeister)

Rene
----

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an early Chuck Close-like portrait (sss+aoi)

Rene
----

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Wow, looking very good.

I think the eyes should be a little more shiny, they look a little 'dry' at 
first glance.

The lips look pretty good.

There seems to be a line over the cheekbone - was that intentional?

I love the wrinkles around the eye, I assume that's modelled or did you use 
a bump map here?

I didn't use your technique in my latest image, but I will soon

        == John ==

"Rene Bui" <ren### [at] freefr> wrote in message 
news:web.4210bb9ef1864a88fc1e93f70@news.povray.org...
> an early Chuck Close-like portrait (sss+aoi)
>
> Rene
> ----
>


--------------------------------------------------------------------------------

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Very interesting experiments, Rene. I should try some of these now 
that I just moved to MegaPOV 1.1... :)

> 4 - I've tried with other 'things', but unsuccessfully.
> [ Jaime : I've tested your 3d cafe skull idea, but unfortunately does'nt
> work here. I don't know how you really did it. 

   I just placed the skull over my current experiments... call it "good 
luck" that it worked with my media setup.

> http://bambousette.free.fr/head_experiment/other_sssexperiment.jpg

   Media is very sensible... what works well for a concrete setup, 
creates artifacts with other conditions. In my tests I did use just 
standard scattering and absorption, and also interior fading:

   interior{
    fade_distance .00001 fade_power 1000 fade_color Red
    media{
     absorption mb*2
     scattering{1,mb}
    }
   }

   with mb set to 3. The image_map uses "transmit all .4 filter all .1".

   After my last post here, I done a few more tests:

   http://www.ignorancia.org/img_page.php?image=0&db=wip

   Looks like it's not a bad idea, but I fear the work required to 
create my own skull, and then remodeling the head to fit the same shape...

--
Jaime

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>Wow, looking very good.
Thanks

>I think the eyes should be a little more shiny, they look a little 'dry' at
>first glance.
You're right, but I was so concentrated on skin problem that I forgot to
work on eyes texture.

>The lips look pretty good.
Thanks again

>There seems to be a line over the cheekbone - was that intentional?
hmm.. not really, there is something wrong here with the model (a too flat
area) and unfortunately the light... :(

>I love the wrinkles around the eye, I assume that's modelled or did you use
>a bump map here?
it's a hand-made bump map.



Rene
----

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>   I just placed the skull over my current experiments... call it "good
>luck" that it worked with my media setup.
>
>   Media is very sensible... what works well for a concrete setup,
>creates artifacts with other conditions. In my tests I did use just
>standard scattering and absorption, and also interior fading:
>
>   interior{
>    fade_distance .00001 fade_power 1000 fade_color Red
>    media{
>     absorption mb*2
>     scattering{1,mb}
>    }
>   }
>
>   with mb set to 3. The image_map uses "transmit all .4 filter all .1".
>
>   After my last post here, I done a few more tests:
>
>   http://www.ignorancia.org/img_page.php?image=0&db=wip
>
>   Looks like it's not a bad idea, but I fear the work required to
>create my own skull, and then remodeling the head to fit the same shape...

Good news !!
I never tried interior fading (I'm definitely a poor newbie !)

Your latest images are very good and instructive.
Particularly these :
http://www.ignorancia.org/images/wip/cabeza-SSS-5.jpg
http://www.ignorancia.org/images/wip/cabeza-SSS-6.jpg

They impressed me.
Make me think that skin is a very very inconstant material.
Sure it depends on what person (age, sex, ethny), what lighting etc.
it can be opaque like this:
http://bambousette.free.fr/head_experiment/LS012787.jpg

or completely waxy like this:
http://bambousette.free.fr/head_experiment/monsterphoto.jpg

I don't want to make a scientifically perfect skin, but if we can do just
something *plausible* I would be very happy !
And after what I've seen on your website, I'm optimistic.

Well, go back to test now with your media setting. ;-)


Rene
----

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Rene Bui wrote:
> I never tried interior fading (I'm definitely a poor newbie !)

   I tried everything I can figure... but at the end this simple setup 
was the most uniform in behavior.

> Make me think that skin is a very very inconstant material.
> Sure it depends on what person (age, sex, ethny), what lighting etc.

   Yes... it's perhaps too complex to have a simple setup to behave well 
in all situations... but we can keep trying. ;)

> I don't want to make a scientifically perfect skin, but if we can do just
> something *plausible* I would be very happy !

   Me too!

> Well, go back to test now with your media setting. ;-)

   No doubt... ASAP. I should try an idea I got after your mention of 
using a double mesh... ;)

--
Jaime

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"Jaime Vives Piqueres" <jai### [at] ignoranciaorg> wrote in message 
news:42112349$1@news.povray.org...
>   After my last post here, I done a few more tests:
>
>   http://www.ignorancia.org/img_page.php?image=0&db=wip

Very impressive, although some of them look a little 'waxy'.

>   Looks like it's not a bad idea, but I fear the work required to create 
> my own skull, and then remodeling the head to fit the same shape...

What about using an image map to do it?

A map would have the advantage of being able to control the effect near 
elbows and knees, which would be a little 'thicker'.

Look at the following product:

http://market.renderosity.com/softgood.ez?ViewSoftgood=34302

This is using Poser's renderer, but the same Aoi trick can be (better) used 
with POVRay.  I have to admit it's tempting to get the product and see what 
the maps he uses look like.

        == John ==

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