Reality Factory

I deleted everything but what shows in game on my static mesh terrain,
now it looks like the fog is showing through the cracks between
triangles for a second as I move over it. I've tried getting rid of
the fog, but the frame rate drops, How do I eliminate the flashes, make the terrain double-sided or something?

try setting Backfaced to true

Backfaced is true, but the mesh has no backfaces, should I make some?

no. a model always has backfaces, they're just the opposite side of the visible face.

i get this as well when using nems terrain. go through and make sure all the seams where you get this problem are snapped and welded in wings or milkshape or whatever.

with the BSP, it seemed the editor put a small space between the brushes when importing. not sure if it's related though.

I meant to duplicate the mesh and flip the normals, that would
be 2-faced I guess. It's not really that bad, another 'feature'
I have to live with, not going to give up the FPS increase. I did go
and weld all the verts, might have helped a little.

I meant to duplicate the mesh and flip the normals, that would
be 2-faced I guess.

no, rendering backfaces means that you can see both sides of a triangle without the need of adding an additional triangle