Steve Shelby wrote:

> I posted my newly completed human head mesh on p.b.i. I asked for
> suggestions or recommendations for skin texture and hair, but none of the
> replies have addressed that. So I'll try here. I'm looking for the most
> realistic effect possible. Any suggestions will be appreciated.
> Thanks,
> Steve Shelby
> 
> 
It's an ongoing hunt at this point.  Traditionally the grail of skin 
texturing is to effect the slight glow created by its translucency. 
THis has been true in centuries of painting long before cg came along.
Traditionally this was effected with variations on the layering of 
translucent paint to suggest the underlaying textures of skin 
pigmentation, veins and so on mixed with strategies of playing the 
chromatic effects of colors off of one another to produce some of the 
visual effects of flesh.   In the renderman world, shaders have been 
experimented with that try to simulate subsurface scattering which is 
another recognition of the layering of pigment effects in the skin.  The 
best cg effects seem to come from the buildup of layers of texture in a 
graphiccs editing program such as PhotoShop then applying this as a 
image map.  That is why I alluded to uv support in Moray in my reply to 
you.  There is of course the possibilility of applying image maps in 
transparent layers though I'm not sure this gains anything over just 
combining layers in PS
In POV there has been some experimenting with subsurface scattering 
effects through filling the object with a dense media and keeping the 
surface transparent.  But this precludes the ability too include the 
textured pigmentation characteristic of skin ( you know freckles ,liver 
spots etc. )  One sss experiment seemed to be about shooting a fine 
layer of blobs from the lightsource at an object and making that somehow 
translucent.  The experiment was done with a candle or figureen I think 
but if I am understanding the technique correctly it might allow the 
combination of layered pigmentation effects with translucent effect.  I 
have tried filling the object with a media and using some sort of 
semitranparent surface texture to little advantage.  Again the most 
powerful illusions I've seen on the more commercial sights have combined 
a highly chromatic texture of skin mottling with an very effective use 
of bumpmapping, ignoring the sss issue altogether.  Other concerns, 
outlined recently by Gilles Tran are the separation of different finish 
effects, specular, reflection, diffuse.  This is done through the 
application of separate maps in commercial apps.  It takes a bit of 
sleight of hand with layering of textures in POV to get this to happen. 
  In short, some component of the texture needs to be repeated in every 
layer it seems.  I have been surveying how this is done in commercial 
apps and trying to apply it to POV.  But I am far from being able to 
discuss it confidently yet.  Applying texture maps is the approach that 
is most likely to pay off.  So you are going to have to get good at 
making uvmaps imo.

Hais is another grail.  Most use the POV pigment_pattern to draw hair 
onto a transparent bit of mesh.  This mimicks the approach of commercial 
software.  I have also been playing with the generation of individual 
hair which may have some limited application.

A couple of links:
 From a recent G Tran post:
"
Regular POV 3.5, 3-point lighting :
http://www.oyonale.com/histoire/images/vicky3_test.jpg
MLPov, Kitchen probe HDRI lighting
:http://www.oyonale.com/histoire/images/vicky3_hdri_test.jpg

I tend to believe that POV-Ray code could make good skin textures but more
control is needed on the finish. What I think is missing is the possibility
to tweak specularity by having more control on the falloff curve and on the
illumination type. Also sorely missing in regular POV is an angle of
incidence pattern (it's in MLPov) which is extremely useful for more more
things than reflection (where it exists in 3.5). Below is the same Vicky,
this time in Cinema 4D with HDRI and specularity and aoi tweaks. It could be
better but it's getting there (and I'm a newbie so there's ample room for
progress).
http://www.oyonale.com/histoire/images/vicky3_hdri_c4d_test.jpg

Below are details of a series of images I did in POV-Ray 3.5 recently (the
images themselves are not on the site yet), where the characters' skin or
fur were rendered with a faked aoi texture using a slope map linked to the
camera:
http://www.oyonale.com/ldc/images/grandrue_est_bleu_detail1.jpg
http://www.oyonale.com/ldc/images/grandrue_est_detail1.jpg
Note that these images are less "genuine" than the previous tests, since
there was a lot of artifact removal post-render and some compositing.
"

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