SSS for Blender? HERE!

[Manuel]

Announce + articles (sss for renderman too)

http://www.dedalo-3d.com/

direct link to article (only Blender) + blender file (basic version):

http://makewiki.aleppax.it/pmwiki/pm...haderInBlender


Regards,

Manuel

[BgDM]

Interesting approach to the issue. Thanks for sharing.

BgDM

[UglyMike]

Very impressive. I'm sure the shader will be picked apart when the boys here get their hands on it! Love the results, but for me, it would be more convincing to do a simple Jade sculpture , a glass of milk, a candle etc. as that would show the effect better. The old man, bacause of how good he looks, makes me wonder how much is attributable to your 'shader' and how much to the model. No such problem with primitives (like Susanne! ) A picture with and without shader would also be nice to judge the effect....
Nevertheless, this seems quite nice indeed. Thanks Manu!

[Manuel]

Originally Posted by UglyMike Very impressive. I'm sure the shader will be picked apart when the boys here get their hands on it! Love the results, but for me, it would be more convincing to do a simple Jade sculpture , a glass of milk, a candle etc. as that would show the effect better. The old man, bacause of how good he looks, makes me wonder how much is attributable to your 'shader' and how much to the model. No such problem with primitives (like Susanne! ) A picture with and without shader would also be nice to judge the effect.... Nevertheless, this seems quite nice indeed. Thanks Manu!

I'm very busy with next reelase of MakeHuman...try by yourself: just apply the same material to a different mesh, using the same light.

Cheers,

Manuel

[The M.h.p.e.]

Impressive!! Just tried the first method out myself (downloaded the example
file and played around). Actually quite easy to get around.

//Mathias

[rexprime]

this great news

[renderdemon]

Only some notes,I'm the author of the Blender techique,I'm helping Manuel with the skin shading.
This is not designed to render deep traslucent objects,is mainly focused on thin surface,like skin.But works for deep traslucent too,the only major limitation is that light is not blocked inside(like bone into the body),for this you must fake.

[Cire]

Thanks for this tip!

Been doing some tests with this technique, and I'm quite satisfied with it. While it does have it's limitations, it's the best workaround I've come across so far.

Until Blender or an external renderer provides me with more accurate SSS effects, I'll be using this one a lot.

Thanks again for sharing, and keep up the good work on the various projects you guys have going!




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[TorQ]

This looks really great! Thanks for taking the time to offer your solution to the community. After looking at the file and playing with some of the settings I still don't have a solid idea what each of them do... I'm hoping with some input from others I'll be able to recreate that nice sking look.

Thanks.

TorQ

[Cire]

Here are the results of my experimentation with this technique so far:



I was going for the general look of jade (green), wax (blue) & skin. I didn't use any photo references for these materials, just memory/imagination.

The skin especially needs work & was the hardest to get decent results from. It looks a little 'waxy' to me . . . and the wax looks a little 'plasticy'. The jade-like material came out pretty nice, though (IMHO).

I'll post the .blend later if anyone wants to check out the settings.

I'm lovin' this method, although there are some problems:
1. Texture maps (esp. bump?) don't work too well . . . maybe nodes could be used to layer the material so as keep the SSS & textures seperate?
2. Complicated multi-layer setups may be needed for a good SSS effect along with proper lighting/shadows for other objects (esp. when multiple types of translucent volumes occupy the same scene & area).
3. Various material settings cause unexpected results (for example: Fresnel has an effect even if transparency is not used; very low specular Hardness values create a sharp light/shade transition - actually looks reflective?).

Anyway, the possibilties are wide open - it even works for animation! Please post if anyone has additional info. In the meantime, I'm going to prepare a short animated version of my test scene for upload . . .




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[cekuhnen]

well a SSS shader would be much better.
that long node seems like a lot of work.

but the results are quite good already.

[Cire]

Originally Posted by cekuhnen well a SSS shader would be much better.

No doubt . . .

Originally Posted by cekuhnen that long node seems like a lot of work.

I assume you're refering to the screenshot of the node setup on their website . . . because I don't see it in the sample file. The SSS material doesn't seem to have any nodes, which confused me after having seen that screenshot (someone correct me if I'm wrong).

Anyway, the material works . . . and I haven't touched any nodes.

BTW: Here's the same test scene animated (the light source revolves around the meshes):

SSS Test - 8MB video




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[renderdemon]

SSS is a layering effect.
There are different type of scattering which need to be taken into account.
The idea here is simple,but the setup to make it work well isn't,and I can't do nothing about it.
My skin shader use different node to modulate the effect based on principal direction and light group to controlling better the contribution of various nodes(or you can always composite the layers with separate passes which is much simpler).I don't have released this skin shader(I have released only the basic setup which do the scattering) because :
A)I'm working on improving it,look here:
http://blenderartists.org/forum/showthread.php?t=78400

Probably I'll make it a little simpler,and much better,but will be always node based,it's more powerfull than a simple shader solution if you know what you are doing(even the mental ray fantastic missfastskin is a collection of node shaders,not one whole thing),the problem here is blender node shading system,which don't support nested group of nodes.

B)I can't give support to it,I don't have the time,you must understand very well how node shading work,and blender people don't have much experience in this field,I'll try one day to do a good tutorial explaining in detail all.
Skin shading doesn't mean only subsurfacescattering,it means even specular shading(a common blinn doesn't work),asperity scattering,darkering shading and so on(I don't have ever seen a shader which do all these things ensemble,you need to break its components to have good control)
Btw,I think Cire is doing a good work here,good looking image !

[cekuhnen]

i agree with what you say in regards to SSS.
however i know solutions which are just a shader because the shader just has the light model inside.

i wish blenders node system will evolve at one time into a real free node compositor and not only a material mixer.

[vistag0]

To Aligorith and animate 78, thanks for your info on "MakeHuman". Seems I posted in the wrong area, but Timothy straightened me out. Live and learn.

[toontje]

Is there a way to use Z-buffer from different angles (like opposing camera angles) to get the thickness of the object in view and from the light source some kind of z-buffer image (or blend texture). Give them all different falloff and stuff, combine them with nodes? Is it possible to map z-buffer values back as textures?

I've read this translucent shadow map paper (for realtime and interactive SSS using Opengl/ DirectX). Basicaly there using the normal image (vector in Nodes), z-buffer and shadowmap. The thickness is obtained (if I understood it correctly) by giving the faces facing the camera a alpha value of 0 and the back faces an alfa value of 1. The scattering is calculated, and in blender we can use python expressions now in most inout boxes. This paper is a bit of though material though, I understan Jennsen's method for SSS much better (I was writing down code of it for Blender 2 years ago, but dropped out of it.)

Anyway, given that in nodes we have access to the shadowmap, vector and z-buffer, it may be possible to emulate this effect in on way or another?

http://www9.informatik.uni-erlangen....h/Research/tsm

[renderdemon]

The problem with zbuffer is that need to be remapped to values in valid color range to be used by nodes shader and for now using python in shader it's not possible,we can only pass information from vertex colors,maybe coding some custom node can do the work.I know that paper(but I don't have studied it too much,their video doesn't impress me too much honestly,but maybe I must take a better look at it).What I really would like to see in Blender is the mental ray approach for their missfast skin shader,it's perfect!
Fast,easy to use and without rendering artifact,I hope someone better than me try to code it.

[roofoo]

Cire: Yes, please do post your blend file, I'm dying to know how this works!

[Cire]

roofoo: Here are the .blend files (one is for the image render above, the other is for the animated version that I posted an AVI from).

Static scene

Animated version


BTW: Unless you have a dual-monitor setup, load the files from within Blender & deselect the "Load UI" button at the bottom.




.

[roofoo]

Thanks, you're awesome!

BTW, I tested to see how I could use a bumpy texture with this technique, and was able to figure out how to do it with nodes. I added a second material, just a stucci noise as a bump map, and used a mix node set at about 0.25 mix factor. So, I guess it will work with a real bump map texture too.