View Full Version : Transparency in JS_MultiLayers for Mental Ray

05 May 2007, 12:10 PM
I made a car in Maya 8.5. I'm using the shader "paint car phenomena" for Mental Ray and it works fine.
I wanted to add some texture on the car so I decided to use JS_MultiLayers.
The pb is I'm getting a black color where there should be true transparency.
When I don't use JS_MultiLayers, the tranparency works well.
I checked "Pass custom alpha channel" in Custom entities but nothing changed.
If someone could help me ?

05 May 2007, 02:08 PM
Are you trying to put a badge or decal texture on top of the car-paint? If so, dont make the shader you are adding as a layer transparant. You need to map the opacity of the layer in JS_MultiLayers instead.

-- David

05 May 2007, 03:05 PM
Thanks David, I tried an opacity texture and it works. The pb I have now using opacity is that the decal texture doesn't have the properties of the car paint phenomena :(. I added a reflexion shader on the decal but the properties of car paint are very specific.
So I guess I should find some options for adding a texture in car paint phenomena but I didn't find anything. It's strange they didn't think about that. But I'm a beginner using Mental Ray so maybe there is a solution.
Thx anyway, I went to ur website, great advices for maya users ;)

05 May 2007, 01:00 PM
Hi Olivier, there are a couple of things you could try.

1. You can map a texture (or shader) to the Dirt_color attribute in the car-paint phen, and them map the decal mask to the Dirt_weight. Obviously this means you cant use it for dirt, but has the advantage of doing the same thing as JS_MultiLayers. But it also has the same problem - no car paint properties.

2. (This is actually the one I would use...) You can map your decal texture to the color attributes of your car paint using a blendColor node and a mask to blend between the decal texture and the original paint color. The decal texture maps to blendColors color1 and the mask to the blender attribute. Color2 would be the color of your car paint. I would use two blend color nodes so that you can map them to the car paints Base_color and the Lit_color.

-- David
(thanks for your compliments too)

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05 May 2007, 01:01 PM
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