I just check it out and I also came up conclusion that this is problem is related to scale. I took my same project and reduce the scale of tree to .900 and it appears to work. I also increase the terrain box side in window and when I this the trees got smaller and did not have the problem. I then increase the scale of the trees and once they got to a certain value, I had the problem. As a developer myself professionally, I believe this is a bug.. but it maybe limitation that we must work around. I believe with knowledge that I learn in last 2 or so days that I can work work around it. It would be nice to know the limits of what is involve. Good news.. I don't have to worry about that part.. and I can continue on with what I was planning... Stewart