look at this video:

http://www.youtube.com/watch?v=mIkJvRazB7Q

it happened after i rtv'ed to change the map and i didnt auto fix itself.

Do you have an ati card by any chance? Looks like the rendering problem ati cards get most of the time if they don't go to the lobby map first after starting up the mod.

I had this problem a bit on my old comp with an ati card, but you can clear it up mostly by going to oc_lobby on a listen server before playing on a different map.

If you don't want to go to oc_lobby every time you start obsidian conflict up you can just install this, I've been using this since fug put it on the database and I haven't had the ati graphic glitch ever since

http://ocmapdb.wikidot.com/map:background-pyramid

i do have an ati.
its an ati radeon HD 5700.
anyway this seemed to fix itself after i changed the map so all is good.