Displacement grass seems to be clumping together??

[ricocacciatore]

Hi, I'm reasonably new to using Vray but I have read through a number of manuals and understand the principles behind it reasonably well. Currently im playing around and getting used to the system by rendering a simple scene ( 3 plastic chairs on a piece of grass). im usings displacement for the grass but when i render it, it clumps together. Heres a screenshot of before the render and after:

Before:
http://i74.photobucket.com/albums/i2...o/ahhAlpha.jpg

After:
http://i74.photobucket.com/albums/i280/o0rico0o/ahh.jpg

Any help would be really appreciated,
Rico

[fpedrogo]

Hi
My guess is that the surface with the displacement is inverted. If you have the back face pointing up you could have that kind of issue. Right click on the surface with displacement and invert it.

Best

[ricocacciatore]

great stuff thats done the trick thanks for you help! Just re rendered and it looks good, the only thing is that the edges of the grass plane doesn't look quite right ( see circled area here http://i74.photobucket.com/albums/i2...ico0o/hj-1.jpg) its not too bad in that picture but when you increase the displacement it gets worse, do you know why this is?

[fpedrogo]

Hi
This is normal, the displacement actually deform the whole geometry to give you more realism into your render. If you see the grass in a real live, you will have some deformation, you will never have a straight edges. If you want straight edges, you should use bump map instead of displacement, but you will not reach the depth that displacement can reach. You can increase the edge length to get more quality on the displacement, but this will increase the rendering time.

Best