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View Full Version : Misss-Fast Skin Shaders on mulitple faces of object?


bjb3812
06-03-2007, 09:06 AM
Hey Guys,
What I'm trying to do is assign multiple misss fast skin shaders to selected faces on my character. I am not using UV sets, all the UVs are on the same set, (for example, I have the front of the face taking up 0,1 on the UV grid, the chest taking up 1,2, back 2,2, etc so each major body part takes up a spot on the UV grid, so I can achieve a higher resolution of textures, rather than putting everything in the 0,1 space and making a 30,000 x 30,000 pixel texture, which would be asurd. So i've created a misss-fast skin shader for each part of the body and each has a color and bump texture mapped. So i select the faces that i would like to be a part of the shader and assign it. The SSS shader works fine if I just assign it to the entire mesh, but as soon and I try to have multiple shaders assign to different poly faces of the same mesh, things start looking strange - either everything turns black, or one of the shaders work, and the other doesn't.
I think it's an issue with the lightmap or maybe the mulitple shading groups, and wondering if I'm supposed to use just one lightmap for the entire model, or a lightmap for EACH shader. The same thing for the MR texture node that gets connected to the lightmap. If so, does anyone have any idea how to connect these in the hypergraph?
If this sounds confusing, a more simple approach to think about is say I have a sphere, and 2 SSS shaders - i want half the sphere to have shader one on it, and the other half shader 2. Any ideas on how to set this up, if it is even possible, would be greatly appreciated.

Thanks!

bwheels02
06-05-2007, 10:07 PM
Try only using one Lightmap. What you are trying to do is possible. There are plenty of objects with multiple shaders attached, double sides shaders, etc. I'll have to think more about this.

TurboSonix
06-24-2007, 08:14 PM
Hey There,

I have exactly the same scenario. I got it right to make the textures use different UVmaps with one SSS assigned to the object. But now I have 2 displacement maps and I can't find a way to make use of both of them using one SSS shader on my model.
So figured I would use multiple SSS shaders, but then I get the same problem as bjb3812.

Has anyone figured a way around this yet?

Anchuvi
07-17-2007, 01:51 PM
Same problem here, I need to use three misss_fast_skin shaders on a single object. One shader works fine but when I apply all three it goes belly up...

anyone know how to fix this?

Ironhalo
07-17-2007, 03:05 PM
have you put your light linking to 2 on the sss nodes and the light map nodes?

Anchuvi
07-17-2007, 04:12 PM
D`Oh! I set it on the Light Map node but not the sss node...

I have sat hee and played around with layered shaders, multiple setups with the light & sss nodes and, as usual, the problem was a simple text box...

Many thanks!

waisze
08-04-2007, 09:58 AM
I'm in the same case too. Is there any method to solve it? It is the problem of lightmap. When we use two different misss in one model,there is no RGB channel in lightmap Lightmap become useless to the model.

Twilite99
10-03-2007, 10:45 AM
This is what you need to do:

1) assign the same LIGHTMAP and MENTALRAY TEXTURE nodes to all your misss_fast_skin_shaders and their ShadingEngines (the misss_fast_skin_mayaSG)

2) in the misss_fast_lmap_maya node and in every misss_fast_skin_shader nodes, there's a attribute called Light Linking which is by default on 0. Put it on the number of skin shader nodes you're using (if your mesh is using 2 skin shaders, put it on 2). The Light Linking attribute can be found in LIGHTS for the skin shaders and in LIGHTMAP SAMPLE for the lightmap node.

3) make sure that there are enough lightmap samples in your skinshaders (I use 512) and that the resolution of the mental ray texture node is big enough.

achoury
10-03-2007, 03:13 PM
Hey Guys,
What I'm trying to do is assign multiple misss fast skin shaders to selected faces on my character. I am not using UV sets, all the UVs are on the same set, (for example, I have the front of the face taking up 0,1 on the UV grid, the chest taking up 1,2, back 2,2, etc so each major body part takes up a spot on the UV grid, so I can achieve a higher resolution of textures, rather than putting everything in the 0,1 space and making a 30,000 x 30,000 pixel texture, which would be asurd. So i've created a misss-fast skin shader for each part of the body and each has a color and bump texture mapped. So i select the faces that i would like to be a part of the shader and assign it. The SSS shader works fine if I just assign it to the entire mesh, but as soon and I try to have multiple shaders assign to different poly faces of the same mesh, things start looking strange - either everything turns black, or one of the shaders work, and the other doesn't.
I think it's an issue with the lightmap or maybe the mulitple shading groups, and wondering if I'm supposed to use just one lightmap for the entire model, or a lightmap for EACH shader. The same thing for the MR texture node that gets connected to the lightmap. If so, does anyone have any idea how to connect these in the hypergraph?
If this sounds confusing, a more simple approach to think about is say I have a sphere, and 2 SSS shaders - i want half the sphere to have shader one on it, and the other half shader 2. Any ideas on how to set this up, if it is even possible, would be greatly appreciated.

Thanks!

hi
set mode to 3 in SSS shader that's all
rachid

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