Problem with grass

Hi
I have a problem with a grass material when I apply it on a surface that I made from contours in sketch up (so there is some hidden geometry there)
I used the material “Architectural green grass”
When I render the image I get some strange lines on the surface of the grass where the hidden lines of the mesh are.

Any suggestions?

Re: Problem with grass

I’ve thought that it might be some shadow created from the difference in the plane but it’s not. I unchecked both cast shadows and receive shadows at that area but still the same result.
Any ideas?

Re: Problem with grass

I am sure I had this problem before but we resolved it, have a search of the forums. I’m sorry but off the top of my head I just cant remember the solution.
In fact as I type this I think we may have shown hidden edges in the model, then selected all the faces and apply a smooth. Try that.