August 14, 2011, 12:44:24 am
My guess is it's to do with Z fighting. See topic here
for some possible workarounds that (may) help.
Based on what I see of the terrain relative to your model, your model is maybe scaled down and you would need for it to be scaled up or re-imported at some other real units scale and make your own terrain relative to the model and bring that in. Someone with more experience could confirm or correct me on this.
Even so, at this stage you may not be able to get rid of all Z fighting issues other than choosing not to have distance camera views for certain shots.