[Gtkradiant] Now you see it, now you don't - walls.

[M Stone]

I built a hallway with several 12 sided pillars running through it.
When I test in Quake3, I can see through one side of one of the pillars. 
(as if there are no polygons there.)

All the other pillars look fine, and they're all exactly the same pillar, 
cloned a few times.

When I shifted it slightly over in the hallway,and re-tested in Quake3, the 
side appeared again.

--> I wonder, why did that one pillar have a missing side, and why did 
moving over a bit help ??