hi again!
omiKron, thanks for your comment!!
tom72, thanks a lot, yes, grass is made with the maxwell's grass feature...
about DOF in vray: you have to create a z depth pass, then in photoshop use that pass to give the depth to your render using the lens blur filter...
the following tutorial is for 3D max but it should work similar with SU + vray
http://www.onnovanbraam.com/index.php?tutorials/depth_of_field/
Carloh, much appreciated! I used SSS (single sided) material for grass, and a texture for the blades shared by Peter Guthrie in this tutorial:
http://www.peterguthrie.net/blog/2009/04/vray-grass-tutorial-part-2/
thanks again, best
V