Using vertex color for texture variation?

[DPGrafik]

I've just flipped through the latest issue of 3D Creative PDF-mag (June issue). There is a walkthrough of Bertrand Benoit's (BBB3) excellent Tribeca loft render. (done in max).

I've noticed that he uses vertex color to overlay certain texture maps. As i understand it, it is to get geometry dependent variations to the texture? I also notice that the vertex color node is present in Maya's Hypershade. However information is lacking, and i can't really seem to get, how it should be used in maya.

I've tried building my own shader to have wear and tear, and somewhat geometry dependent. I use the dirt node with invert normals and a black and white map in the radius slot, as a mask between two textures. And also a remap value version of the dirtmap as a reflectionmap. Is that the way to do it in maya? or is there still a need for the vertex color node?

Any help is appreciated

[vlado]

To use the VRayVertexColors texture, you need to create a color set for the selected mesh(es), paint some vertex colors, and then link the name of the color set to the VRayVertexColors texture, for example:

1) Create a sphere
2) With the sphere selected, go to Polygons > Color > Create empty color set
3) Select Polygons > Color > Paint vertex color tool []
4) Paint some colors on the sphere
5) Assign a VRayVertexColors texture to the diffuse color of the sphere material
6) In the Outliner, select the sphere shape (not the transform)
7) Go to Windows > General editors > Connection editor
8 ) Open the Hypershade, select the VRayVertexColors texture and load it into the right slot of the Connection editor
9) Connect the colorSet.colorSet[0].colorName attribute of the sphere shape to the colorSet attribute of VRayVertexColors
10) Render

From then, the usage is the same as in 3ds Max. More information on the VRayVertexColors texture is available here: http://www.spot3d.com/vray/help/maya...ors_params.htm

Best regards,
Vlado

[DPGrafik]

So this could be a more manual way of painting a dirt map or object mask to use in a given shader network, or does it has other common uses?

[vlado]

I don't think there is a particular use case for this; you can use it for whatever you need - e.g. for VRayFur distribution or direction masks, sss2 radius multiplier to make e.g. the ears of a model more translucent and so on.

Best regards,
Vlado