[Fernando Tella]

Hi,
I don't know if this is a bug, the right way of doing it or maybe something I don't understand right. Let's expose the problem:

I'm using grass modifier in 3dsmax 2012 and I'm trying to map the surface of the object. As stated in the documentation I should use channel 1 instead of 0 which in 3dsmax translates to 2. Ok, my material is set like that, then I apply a UVW mapping. To be able to control the surface mapping I have set uvw mapping to 1 instead of 2. Is that right?

Maybe you did that on purpose as root to tip does not need uvw mapping and changing the channel would need an extra click but it confused me for a while. JFYI.

[Mihnea Balta]

The base mesh and the grass are different objects. For the base mesh, you should leave the mapping on channel 1, since that's what the grass object will copy. The grass object automatically generates root-tip UVs on channel 1, and will copy the UVs of the base object on channel 2. This becomes a problem when you're using the same material on the base object and on the grass, since the UV channels cannot be specified per object. In that case, you should add channel 2 on the base object, copy the UVs from channel 1, and use channel 2 for all the textures.

This ordering used by the grass object is a bit awkward to keep compatibility with the Maxwell hair object, since they can be used interchangeably in some cases.