njon posted a similar question recently but hasn't gotten any replies. He was trying to texture some crates I modeled on my computer but they went transparent, everything else was fine. Well, I just started modeling another scene tonight and about 2 hours into it, I tried to texture some tunnel walls and guess what happened, they went transparent. Hmm. I have no clue to what's causing it. Everything else in the scene is fine. Lights, buildings, roads, etc, it's just those walls. Does anyone have any ideas that might lead me to an explanation. Any thoughts you have would be greatly appreciated.