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Parthius
07-21-2006, 04:37 PM
I'm having trouble getting the SSS Omega node to work. It's probably my inability to correctly parse the directions:

"needs either a layer of flipped conforming polygons... or Double sided turned on in the surface Editor and taken advantage of via the Spot Info node by using its Polygon Side output as an input to the opacity input of a mixer node connected to the two surfaces."

Nothing I tried worked right. Anyone know how exactly I'm supposed to connect the mixer node to the two surfaces? I tried both a flipped layer and simply turning on double sided.

BTW, Kappa worked easily...

Celshader
07-21-2006, 05:53 PM
I'm having trouble getting the SSS Omega node to work. It's probably my inability to correctly parse the directions:

"needs either a layer of flipped conforming polygons... or Double sided turned on in the surface Editor and taken advantage of via the Spot Info node by using its Polygon Side output as an input to the opacity input of a mixer node connected to the two surfaces."

Nothing I tried worked right. Anyone know how exactly I'm supposed to connect the mixer node to the two surfaces? I tried both a flipped layer and simply turning on double sided.

BTW, Kappa worked easily...

Here's one example. In the node graph shown in the image below, the FG Color of the Mixer is overlaid on top of the BG Color of the Mixer. So, the green FG Color completely wipes out the red BG Color underneath as long as the Opacity is 100%. If the Opacity is 0%, the green fades out completely, and only the red shines through.

The Polygon Side output of the Spot Node marks the frontside of each doublesided polygon as white/100%/1.0, and the backside of each polygon as black/0%/0.0. I plug this Polygon Side output into the Opacity input, overwriting the internal Opacity of the Mixer node. Now the Opacity of the green FG color will be 100% opaque on the frontside of each polygon, and 0% opaque on the backside of each polygon. This is why the frontside of these double-sided polygons are green and their backsides are red.

This is good for applying different color textures/imagemaps to each side of a double-sided polygon. Plug one color texture/imagemap into the BG Color, and another into the FG Color, and you'll have a double-sided surface with different textures on each side.

-+-

For different Luminosity/Diffuse/Specular/(anything with a "green" input)/Translucency settings on each side of the polygon, consider using the Logic Node (Add Node->Math->Scalar->Logic) instead of the Mixer. Plug the Polygon Side output of the Spot Info into the Logic node's "A" input. Set B to 1.0, and the Operation to "A Equal To B." With this setup, the frontside of the polygon (1.0 in Polygon Side terms) will equal B (which is also 1.0), and the Logic node will use the number in the "If True" setting. The backside, which is 0.0 in Polygon Side terms, will not equal B (which is 1.0), and the Logic node will use the number in the "If False" setting.

With the setup shown in the second node graph, the frontside of each doublesided polygon has an Index of Refraction of 1.3. The backside of each doublesided polygon has an Index of Refraction of 1.0.

Parthius
07-21-2006, 08:31 PM
Fantastic! Much thanks!!!

Karmacop
07-21-2006, 08:38 PM
Here's an example surface that uses the omega shader. It uses the omega shader and a lambert shader mixed together for the diffuse shading, and a phong shader for the specular shading. Note that the surface is double sided and the logic node is used in places with the polygon side output to change what the surface does on the two sides of the polygon. You may need to go into the omega node and change the penetration distance depending on the size of your object.