Getting U and V coordinates in Xgen Core

[denisVFX]

Hello. I try to create feathers system with Xgen in Maya. I encountered a problem derivering U and V coordinate of surface on which xgen primitives are generated. By default UV coordinates are uv positions of each hair strand (U along hair and V across hair primitive).

I tried to create a custom  shader parameter in Xgen description with value $dPdu and $dPdv. But it works strange. And it works totally incorrect when I try use V coordinate (along strand) and my custom user data as UV coordinates of texture file.

I wonder that there is no easy way to get this coordinates.

Baking color data from texture is not sutable in my case, because I need to apply taxture along strands and some U or V coordinate of source geometry...  What could be a right solution ?

[denisVFX · Accepted solution]

Ok. I found one solution. But I'm not sure if it's the best one.

In Xgen I added custom two custom shader parameters. $v (represents v component of each face) and $faceId 

And created shader network which with simple math operations calculates linear ramp from v and face id.

For multiple feathers $faceId must be modulated by 17 (It's polygon count on my source strand geometry from which I generate xgen geometry).