Vos80

Maybe someone stumbles across this topic like me. I had the same problem with the leaves of a tree disappearing from certain angles. In my case, it turned out that the scale of the mesh of the tree I was using was 10, because I had to bridge it through 3ds max to make it a *.nif. I fixed it by resetting the xform (under utilities tab of the command panel).

This was incredibly helpful, thanks a lot!