How to create subsurface scattering?

[ldunin]

Hi. i've been trying to get a subsurface scattering method but without succes.

I was trying to use specific mr shaders and something like this:

blinn
[suppress all maya shaders] ----> material
shader
(dgs_material)

                                                     photon shader
                                                 (dgs\_material\_photon)

i've connected a spotlight to the light array of these nodes and i've used a caustics configuration.

I saw some tuts using volume shader and phot_volume shaders but the results are not so good.

'The dgs_material material shader can simulate mirrors, glossy paint or plastic, anisotropic glossy materials such as brushed metal, diffuse materials such as paper, translucent materials such as frosted glass..'

I was looking for extra information and i only found a shader for xsi called TranVol
http://www.andymator.co.uk/shaders/tranvol2/

I'll be working on this.. but if somebody can help, will be appreciated.

[latrommi_suineg]

http://www.motiondesign.biz/

[ldunin]

i've already checked that. In that tutorial, he's using a phong shader with a volume and volume photon mr nodes. I'm looking for physically correct shaders (dgs) to get glossy transmission or specular transmission.

I think i'm getting closer to the right values.

with shinny to 0 as well as glossy, and ior set to 1 (transp >= 1).

[user_deleted]

you can always look back at siggraph paper if you need alot of help, I always wanted to make a good method for doing sss, but never got around it as its more heavily dependent on eventually writing shader, and I try avoid that if it can be done in hypergraph....

[ldunin]

Hi , well.. good news.

" tranvol2 shader is not really a SSS shader. Its more a sub surface
illumination, with minimal scattering.

Primarily it works by assessing the volume space from the rendered point in the direction of the light sources and it then uses that information to calculate any extraneous illumination. It doesn't use scattering properly yet so there is no bleeding of light across the material.

I (Andy) made it as a bone shader experiment for a personal project but most people seem to want to use it for skin - it'll help show light coming through thin sections of material - ears, nose, etc but it needs some more work before it can be used to make nice translucency.

You can use this shader in Maya too - someone has mailed me the plugin code for integrating it. I'll find it and post it up on my site.

Andy "

http://www.andymator.co.uk/shaders/tranvol2/index.html

Now, time to make some tests.

[4now]

i am testing your node at the moment ! some questions:
1. suppress maya is set to on ? do i have to make settings in the mayasection or in the irradiance/mental ray or is everything inside your node ?
2.your node is connected to the material section ?
3.do i need additional nodes (like photonshader,...)

okay i have read that you are not familar with maya
so i hope that anyone works on this node too.

[ldunin]

• I've added the mr shader to an empty slot in a blinn shader (and i've checked the suppress maya shaders)

• yes.. to material section in the mr shaders section

• no. At least for the test i've done i've only used the tranvol node.

i'm familiar with maya and i've asked Andy about his shader in xsi (then he gave us this release).

Be sure to use point lights. I've tested area, spot and area and no good results.

The render may be take long times to finish, be sure to render in production quality when you are satisfied with the look of it in preview.

At the moment, i'm working in more tests and planning a help file for maya users.. =) hope to finish this soon.

Byep

[user_deleted]

Well, apparantly "true" subsurface scattering is possible via Mental Ray, as XSI does it via Volume Effects shaders...

now, initially I thought the Volume Effects was just a fake, similar to the method at www.motiondesign.biz but a colleague of mine who uses XSI extensively told me that it was "real" SSS, not faked...

if this is true, then XSI has a method for "real" SSS via Mental Ray.

What we need is for someone to develop a shader for MR for Maya that works like XSI's Volume Effects, or have someone convert Volume Effects to a MR for Maya format...

The latter is doubtful, as Volume Effects (I believe) is integrated into XSI and not a separate shader.

Anyway, as I am not programmer I would not be the person for the job, but perhaps someone out there is up to the challenge ; )

While they're at it, perhaps they can develop a utility for easily connecting/disconnecting lights to DGS shadrers? Connection editor/mel script/hypershape methods are rather annoying... Just a thought ; )

-Steve

[ldunin]

Well, even with a real SSS if the rendered image isn't visually pleasant it doesn't work.

But somebody's working right now :

http://lightengine3d.com/downloads/plugins...ubScatter1.html

Just take a look

[filoux]

Hi tried Motiondesign tut , about it
but,what appears in hypershade,there's no connection made between
parti-vol1
transmat photon node
Should i make connection "manually" output to input
can,t see anything such,in hypershade
result in rendering is a simple ,almost ,black ball
with some spots of reflection & refract
how should i see the connections
txs in advance

[ldunin]

Hi.. well.. that's weird.. If i'm right, that tutorial was using maya 4.5 (I don't remember) .. if u get a black hole there, then u need to make that connection manually.

U can open the hypershade, select the shader (blinn1) and graph network. That action will display blinn and blinn2SG or something like that.. the mental ray specific nodes are connected to the blinn2SG . U can also drag the lights to the hypershade and you'll see the connections between lights and mr specific nodes.

http://www.prodigyweb.net.mx/jclepev/tuts/mvs/screen13.jpghttp://www.prodigyweb.net.mx/jclepev/tuts/mvs/screen13.jpg

To add the light, just ctrl + left click and drag the light onto the mr shader. Connection editor will pop-up just select from left: message and from right Lights[].

Hope this help you

[filoux]

all right
txs very much for replyin,
i,m answerin, very late
anywy; i,ll try now

[filoux]

i have screen shot about hypershade ,but can,t attached here
do u have @??