I cannot apply a paint grass in a plane who is made of sandbox in sketchup

how can I apply a grass paint assets in a plane made of sanbox in sketch up, anybody here can help me out.

I would try with grass texture and displacement or with skatter.
But with such a large area and zoom, your PC could be overtax or slow.

Hello, please try reversing faces in SU, then apply grass again. Also we will have grass materials in 2.0, which will avoid this kind of problems.
If the model still cannot apply grass, feel free to let me know.