Skin Shader study

#1

Some test rendering with messiah for skin shading.

I went with a multi-pass setup, so I can have more control over the final comp to get the desired result.

  1. The first thing I do is render just the color + SSS. The base color is light flesh color and SSS extend color is red. My SSS option is set to extend shade, which worked the best for skin in my test. Ext Amt is .5, Ext Depth is 5, Strength is .4 and inset is .001. I originally applied an AON Cel node to blend in sub-dermal vein texture, but opted out to comp it separately using screen for better control.

  1. Here I comp a separate specular layer using screen again, to apply oily skin look.

  2. I used fresnel-grad from the camera factor to get the velvety texture of skin. I used screen here again to comp.

  3. Now this was an experiment. I first used an ambient rendered layer, but it didn’t give me what I was looking for. I played alround with the idea of using IBL with an HDRI image. Once I got it into PS I blured the image enough to get me a IBL cheat. It worked, but in the future I will opt to blur the HDRI image map instead of bluring the final rendered result.

  4. The reason for what I did in 4 was to use it in an ambient occulsion setup. Here I just render with No Bounce Light GI, MC at 12 and depth at 1. I used No Bounce Light, because all I needed was the shading quality of GI and nothing else, it also renders fast. Once I brought it into PS I lowered the saturation and multiplied the layer.

Cheers,

#2

Fantastic image you have going on for your skin study.

Can you post images of your Photoshop layers with the layer setting (multiply, screen, etc) and intensity?

#3

Very interesting approach to create multipasses and reassemble everything in Photoshop or perhaps After Effects if it were animated. Very cool, Tony. I remember Maria when we first started posting on the Silo forum. And I remember your skin studies in C4d as well. Time flies when we’re having fun, I tell ya’. Thanks again for sharing your experiments. Always inciteful as usual. :slight_smile:

#4

great test tjnyc!!

#5

Thanks fellows!

  1. Color Layer
  2. The vein layer was screen about 50%
  3. Specular was screen 100%
  4. Fresnel-Grad was screen 100%
  5. Ambient Reflection layer was screen at 100%. I also lowered the saturation about -25
  6. Occulsion layer was multiply at 100%. I lowered the saturation all the way down till the image was black and white. You can play with the brightness/contrast, but I didn’t in this case. I would if I wanted to match a bright day with over exposure from the light .

Cheers,

#6

Thank You!

Do you have anymore information on your IBL cheat?

What was inthe render that you lacking and had to come up with your own method.

Did messiah lack something or just frustrating to pull it out. How would you animate using your cheat? Rotoscope?

#7

Here is an update.

I used a blurred HDRI image map. HDR prefilter ON with HDR intensity at 0.4. No Bounce Light GI, MC 6, depth 1 and GI Nosie reduction at Photons 500000, radius 100, count 400. Took about 30 seconds to render. I like the result better as it is less waxy than the previous PS blured indirect illumination layer.

Julez, the IBL cheat idea I was referring too comes from this article.

http://www.andrew-whitehurst.net/amb_occlude.html

I didn’t follow the whole approach, but what I did with the HDRI was to get my indirect illumination from the HDRI environment map.

Cheers,

#8

Hey Julez,

I don’t think it really is a matter of what the renderer is lacking, it is just the nature of the beast. Here is another shot with some color correction on the indirect illumination layer. Using a compositor to make these changes over re-rendering saves alot of time. By rendering the indirect illumination layer separately I have greater control over matching it to a live-action sequence or just improving the lighting without having to re-render sequences over again.

Cheers,

#9

I am curious in your HDRI pass because you choice of hdriimage or even your cheat before had a great “flesh” look to it. Its nice and warm. I am wondering what you would od different if say you had a sky and beach hdri map. You don’t have a flat “texture pass” but your model looks like skin. The AON cell look pass contributing?

#10

hey tony…i remember your c4d sla tests on this character…and its good to see a slightly different approach in messiah. i like the end result…seems a little specular/shiney in parts…some areas you really nail it stomach and neck i quite like…i like some of the luminous feel to some of them makes it more convincing for me at least…i think you vein layer really does the trick at first i thought it was a little over the top but when you see it in conjunction with the other layers it helps to flatter the image.
good work bud as always…keep messing.:buttrock:

#11

Hey Tjync.

I would suggest the following for you ambient occlusion pass… Set it to linear burn at 15%, create a copy of that layer, set it to multiply at 90%-95% or something… Now go to curves for the multiply layer, and for the R channel set the blackpoint to 128, and for the green channel the black point can be 64 so it get a nicer brownish tone… This way you dont end up with the “grey/black” shadows that usually is obvious with just a regular multiply. I atleast find it much better looking.

/Regards Peter K

#12

Peter,

Thanks for the suggestion. The grayish issue was bugging me as it doesn’t look right in an outdoor setting, but fine for indoors.

Cheers,

#13

Another update, higher-res version than the last ones.

Changes:

  • Followed Sniffet(Peter)'s suggestion
  • Created a better specular pass, really like the way messiah handles specularity, it usually is a b#tch in other apps to get it looking right.
  • Brought out the vein pass more.
  • Added freckles, subtle, but if you look around you will spot some.
  • Got rid of the over wet/waxiness look.
  • Slight PS glow.

I am pretty happy were this is going, need a texture map, some eye balls and teeth and we are almost in business.

Cheers,

#14

I used the St Peter’s probe HDRI map, but I think you could use any HDRI map and still get the same quality of “warmth” illumination. If I went with a sky, I would add a slight blue on the occulsion pass or create an ambient pass with a slight blue and multiple it with the occulsion pass. For the beach HDRI I would use it in my indirect illumination pass. If you know of a good beach HDRI map, I would like to try it out with this series of test.

Cheers,

#15

Looking Great!

#16

Getting close, Tony … getting real close… :slight_smile:

#17

http://debevec.org/Probes/

Go here to get your beach hdri map…

Julez out.

#18

Here is what I got from the beach hdri. It was abit overcast, so I raised the brightness a little bit.

Cheers,

#19

I thought I’d keep things tidy by posting my skin studies here with Tony’s. And it’s also a way of bumping up his very informative thread. Julian posted a Maya SSS shader here which prompted me to investigate the subject matter using Taron’s Basic Shader. This is the Butch character with a little more sweat applied, this is a straight render, no post work:

#20

Looks good! How many lights are in there?