Maya SSS problems.

[Stahlberg]

I couldn't get this shader working at all in 6, the included scene files render okay but as soon as I try to make a new shader and apply it, even to the same geometry, something goes wrong with the connections. I tried connecting in the hypershade, multilister, drag-n-drop, manual connecting etc... There's something different about my connection compared to the existing one in the included files, can't figure it out, I asked Wang Wei in another forum but so far no reply.

[ush]

I'm using maya 5.0 and,I tried this shader too.

First time when I tested.Color texture mapping doesn't work like you said.
so, I connected texture map to bump map and,I changed bump Intensity to 1.
Ater this I also connected texture file to color attribute with middle mouse button drag.
Then cut the bump map connection and, suddenly mapped texture showed up to
HyperShade's material thumbnail.
I could render it but, problem is as I turn Bump Intensity to 0 and the texture disappears.
Ofcourse I also can't use bumpmap too.
I tried like this but,you can use texture map just connect color and change bump intensity.
I think color has some kind of relationship with bump Intensity.
but, I can use a single color(value less than 0.9) withtout bump Intensity.
I don't know why.......

sorry for my bad English.

[Seven]

Thanks for the reply guys. Sorry I didnt reply earlier, just got back from a holiday in DisneyLand :thumbsup: :thumbsup: :thumbsup: wicked.

Anyway, ive found other SSS shaders for Maya and hopefully I can get one of them working. One I am very hopeful for. Once ive recovered from my holiday ill give it a go and post an update.

Cheers

Sevv

[winata]

I managed to get it to work (well sorta, :))

a few notes:

1. you have to do the "connectAttr xxxShape1.worldMesh bssrdfShader1.inputMesh" as he instructed on his website. xxx is the name of the surface node, and bssrdfShader1 is the shader that you created.
2. again as mentioned on his site, only one shader for one surface (i haven't tried poly-combined-surfaces) ... lemme know if this works too :D
3. oh yeah ... only polys ... no nurbs ... step #1 will not work if the surface is not nurbs ...

here's a test image i did a while ago:
http://www.pickledcarrot.com/skinTest.jpg

here's the setting for the image:

color - skin color
bump map - simple noise map, with .001 intensity
diffusion : .42
diffuse reflectance - reddish skin color (there's a note on the website saying to keep the Value above .9, so i did)
scatter length 1.0, .15, .15 (i'm not very sure about this, but it affects R-G-B value on the sub-surface scattering - this depends on the size of your geometry too).
accuracy - .6 (smaller - more accurate)
point Density - .8 (smaller - more dense - becareful, it's exponential, not linear)

I'm still experimenting with this shader ... somehow when i put some color maps, the texture maps become blurry ... i don't have much solution for this yet ... ANYBODY please ???

Keep this thread running if possible ...

anybody knows other way of rendering bssrdf/SSS in Maya, Renderman or Mental Ray?

[winata]

i managed to get it to work ... well ... sorta http://cgtalk.com/images/smilies/grin.gif

here's a test i did with that shader:

http://www.pickledcarrot.com/skinTest.jpg

the setting for it:

color - just some skin color (you can use file texture map for this too)
bump - noise - with very very low intensity (i only want it to be seen when we're really close to it)
diffusion - .42 - .6 depending on the look you're looking for
diffuse reflectance - i put some reddish skin color ... not the Value of the color should be above/around .9 (i believe he noted this on his site)
scatter length - 1, .15, .15 - i believe this refers to R-G-B value ... this will depend on the color of your skin or whatever material you intend it to be plus it depends on size of geometry)
accuracy - .6 (lower more accurate)
point density - .8 (lower - more dense ... careful it's exponential - lower - slower)

specular - set it as you like

Mr. Stahlberg:

the problem that you encountered, i believe it's caused by the connection of the attribute that's already there on the previous shader. as noted on his site, you can only connect one shader to one geometry, and then you have to run the - "connectAttr xxxShape1.worldMesh bssrdfShader1.inputMesh" to connect it ... if there's already a connection from previous shader, you have to somehow disconnect it first before connecting it to the new shader you just created.

remember (noted on his site too) :

no nurbs - poly only!
point light or spotlight only (i used spotlight)

one problem i have ... whenever i connect the file-texture map, it gets blurry ... if anybody finds any solution ... lemme know http://cgtalk.com/images/smilies/smile.gif
Anybody has other ways to do bssrdf/SSS in Maya render, Renderman or Mental Ray?? Please let me know ... keep this thread running if possible ...

thanks ... hope that helps http://cgtalk.com/images/smilies/grin.gif

[winata]

sorry for the double reply :D .. i thought i failed to post the first time ... i didn't know that if you have less than 5 posts, it takes up to 24 hrs to get the stuff posted (for verification) ...

[winata]

sorry for the multiply posts, but here's a few other info i left out ...

The render is done with maya-raytrace, with 6 spotlights (raytrace shadows - i believe depth map shadow will not work)

[Seven]

Hey, could you post that scene file for others to test plz. I still cant get a file texture map to show up.

With this:

connectAttr xxxShape1.worldMesh bssrdfShader1.inputMesh

If my mesh was called cube, that above would change to this:

connectAttr cube.worldMesh bssrdfShader1.inputMesh

thats how I see it. Or are you saying it should look like this:

connectAttr xxxcube.worldMesh bssrdfShader1.inputMesh

.. and the xxx needs to be something else ontop of just cube.

You say your problem is when you use a file texture made elsewere as a texturemap it becomes blurred. I still cant get a file texture (jpg from PS) working period.

[winata]

i can't post the scene file ... it's a client project ... sorry ...
to answer your question:

connectAttr xxxShape1.worldMesh bssrdfShader1.inputMesh

if the name of your object is "cube" then it should be written as:

connectAttr cubeShape.worldMesh bssrdfShader1.inputMesh

or

connectAttr cubeShape1.worldMesh bssrdfShader1.inputMesh

look at the name of the 'shape' for your object (under the channels or in the attribute editor).

this is assuming that you've only created one bssrdf shader and haven't renamed it (by default the first bssrdf shader created will be called "bssrdfShader1")

Hope that helps ...

[winata]

here's a sample file ...

http://www.pickledcarrot.com/junk/sssTest.ma

hope that helps ...

[Stahlberg]

I know about those limitations, and I checked and rechecked my file when it didn't render.
I downloaded yours, and it renders fine, and I can delete the cube and import any polygonal object and drag/drop the shader over it and it still renders sss... this just didn't work before. Don't know what's different either. :shrug:
Thanks.

[Seven]

Thanks for that scene. Very useful :thumbsup: . Its odd, in your scene I can use a texture painted in PS as the colour. However in any scene I create I cant. Also the visibility of the painted texture in the colour channel seems to be linked to the intensity of the bump. 0.0 intensity and the texture is not visible, the greater the bump intensity gets the more pronounced the texture is.

Also I dont fully understand the set up of your scene, the camera also seems to be linked to the visibility of the texture map in the colour channel. Seems odd to me. If you delete the camera the texture isnt visible regardless of bump intensity.

But thumbs up to you for posting that!

[ush]

Thanks for your scene Winata.
Like Seven said, I think there must be some visibility relationship between
bump intensity and color.
This is the test render. I made this from new scene file.

http://u-asutarisuku3.pino.cc/tmpfile/test.jpg

no bump map file, bump intensity 1 ,with color map file.

I think your blurry color map problem is because of your low bump intensity.
Anyway I can't use color map with bump map....

I'm not good at English I hope you could understand what I mean.
Sorry for my bad English.

[winata]

wow! thanks for the tips guys ... the bump intensity thing works ... i can put the color map now ...

if you increase the bump intensity, as you mentioned, the color map becomes less blurry plus the difussion becomes higher (you might want to reduce the difussion value to counter balance it).

I'll experiment more ... i'm swamped with work right now, but if i have any progress, I'll post it here ...

PLUS ... if anybody can solve this too ... it doesn't recognize light linking. In fact, you can't hide your lights in the scene. It will take into account every single spotlights and point lights in the scene, regardless they're hidden or unlinked, or even when you turn off "illuminates by default" in the light attribute editor ... any idea, anyone?

Ush, i managed to have both bump map and color map ... you control the depth of your bump map in the bump2d node ... i haven't experimented far enough on this ... i'll post it when i find something new ...

thanks again!

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