realistic SSS Snail shader

[phix314]

I think you may need to use translucency maps with some over the top sss numbers. What does it look like with too much SSS?

[SanjayChand]

Make sure your lightmap is working right and add more lights (atleast key, fill, and rim). The SSS shader (in Maya anyhow) is very sensitive to light and the look can change quite a bit depending on how many lights one has.

[kanooshka]

A good test for sss is to set the diffuse and dermal layer's weight to 0 and then just work on subdermal separately. Then you know if it's working well.

[TheBeals]

Thanks so much for all the responses! I was able to have time to work on it. I started off with a completely different shader and adjusted the lights and saw a much better sss effect right away. Here is the result that I have thus far:
http://jdbeals.com/snail_test.jpg
A version of this where the sss is completely blown out is here:
http://jdbeals.com/overscatter.jpg
So there is plenty of translucency in both images, but no transparency, which I don't think sss offers? I tried plugging a blinn with translucency and transparency into random slots (overall color, diffuse, front sss...) , but I didnt get any good transperency results. Is there a way to create a transperency map for the sss shader? Or should I scrap this idea and just use a more complicated blinn?

What does everyone think of the shader so far? Any furhter advice would be most appreciated. Thanks again for all the help so far, it looks so much better.
EDIT:
Oh and there is also an HDR image used to help with lighting and reflections :)

[BenDstraw]

i'd say the specular is little strong right now. maybe experiment with some specuar maps?

[wurp]

Concider using glossy refraction too, with a falloff color so that the color becomes deeper the thicker the surface is. I think that combined with sss should give you decent results.

I never found the misss_fast shaders to be any good for really translucent materials like this.

[kanooshka]

If you look at the photos you provided you'll notice that the diffuse value for the snail is very low. Try using a dark diffuse and dermal color. Then if you notice that most of the light is a reflection and also that back scattering and subdermal scattering is very prominent.

[SanjayChand]

You need to play more around with the back-scatter and increase it so it shows up on the eyes. Right now everythign seems very even as far as SSS contribution. It needs more variation.

Also you should paint a color map, lower the spec, and add a little bit of reflection. Your diffuse is also high.

[ezdz]

If you're using the Miss fast skin shader try changing the scale conversion number (lower it to get more scattered light, raise it for less)

[TheBeals]

Ok so I fought and fought with the fast sss. I even cranked the backscatter to 60 (my guy is 35 long and 10 wide) messed with the scalar conversion, lowered the diffuse value and still wasn't getting a result that I was too pleased with (better, not not too great). So I opted for a material that I knew better, the mia_material. I was then able to paint a transparency and translucency map, and had better control over the glossiness of the reflectivity and the refractiveness. Had a great image and then realized that my hdr image was somehow was broken and not doing what it should be doing so I deleted it, new scene reimported snail and reset up hdr and everything got blown out, so I lowered all my values, put a couple eye stalks in his eyes like you can see in a couple images and have come up with this image:
http://jdbeals.com/final_body.jpg
Again its closer, looks a little better. I think along with this, maybe model in some innards to break up the translucency and transparency a little more. The shell is a stand in right now, I'm going to dry it up later and add some more detail and tlc to it. What do you all think? What needs to be tweaked? I'm thinkin up the reflectivity a little, broaded out the spec, lower the diffuse weight a bit? Thanks again for all your help everybody, it is much appreciated!

[ndeboar]

Hey,

Set your front scatter to a grey/dark colour, back to a more pinkish one. Tweak your scale till it looks like your reference.

Keep your reflections nice a glossy.

Spent a couple minutes whipping up an example:
http://forums.cgsociety.org/attachment.php?attachmentid=138862&stc=1

BTW: How did you do that snail shell?

[TheBeals]

OMG. thank you so much for your response, that example looks amazing, I can't wait to try this out for my own. I'm in the process of moving to a new apartment, but hopefully I can get some work done on it tomorrow. What did you do for your lighting? Did you do anything that helps bring out the sss effect or is it just a couple of lights to bring out the details? Right when i had given up on fooling with the sss shader, you managed to bring it back.

As for the shell, it's really simple, but took a while to get right, I dont have any files with me right now to get the exact values, but basically I used the Mia_material(arch and design) as the shader. I applied a displacement map create through zbrush, which helped create the diffuse map which is a bunch of different textures thrown together, which is turning out a lot blurier than I would like and then a spec map. Lots of gloss and lots of relections was used. I can't remember if I used falloff on the relfections, and I believe I used the fresnal falloff of the BRDF. i should be able to post more accurate descriptions later tomorrow. Modeling is simple in theory ( a simple loft) but it took much longer than it should have to get it right :)

[ndeboar]

Just two lights. A point behind the snail to bring out the SSS, and an area light for the fill.

[TheBeals]

Here is a newer version of the snail. The sss is much more apparent. Finally was able to get to act like it should. I'm thinking maybe I should tone it down just a smidge. The diffuse has been lowered greatly and has a much lower weight, the back color has a much greater radius and weight as well as a greener color. I have a color map on this as well as a displacement, and a small bump. I created a very tight spec and a softer secondary spec. I upped the scale a lot. Let me know what you all think and what my main focus should be right now (translucency, specular, reflectivity, diffuse). Thanks again so much, guys.
http://jdbeals.com/final_shader.jpg

[kanooshka]

Try decreasing the scatter radius and changing the scatter color to more of a red or pink

[TheBeals]

As for the recent advice of Dan, I have come up with this:
http://jdbeals.com/final2.jpg
Lowered radius, lowered the depth a smidge and added an environment that it can reflect. It looks much better! Thanks so much, Dan. What do you think?

[kanooshka]

Looking better! I think it will be much easier to tweak more if you put it into an environment.

[ndeboar]

cool, but to shinny ;)

[BenDstraw]

looking much better but i cant help but think you are overexagerating the effect a little. I do like the shell though

[TheBeals]

Well, I figured it was about time that I posted an update for this guy to show you what your help has created. Here is the latest.
http://features.cgsociety.org/newgallerycrits/g74/313174/313174_1237431955_large.jpg
and this is GIANT SNAIL (quick composite for now)
http://features.cgsociety.org/newgallerycrits/g74/313174/313174_1237432444_large.jpg
I'm losing detail in textures and will need to up contrast and and mess with the bump/displacement of the shell to get it to where I want it. Much better though. That weird thing that is near his mouth is a blade of grass for the girl snail :)

Thanks guys for all of your help, it did so much. Let me know what you think!
~Cheers

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.