Anyone seen this fur weirdness before???

It’s a checkerboard-like pattern on the fur (grass).

looks like a mapping issue of some sort

I didn’t map the grass - just applied a simple Vraymtl to it.

What kind of shadows are you using?

Best regards,
Vlado

I’m using a VrayLight Plane.

I don’t get the problems with VraySun

Hm, do you maybe have a scene that you can send over for investigation?

Best regards,
Vlado

Vlado,

I emailed it to you @ vlado@chaosgroup.com.

It almost looks like it’s been manually double-sided. IE. duplicate, flip normals, merge. Does changing the secondary ray bias affect it at all?

Vlado,

Did you see anything strange about the file I sent you?