Update: Solved the issue. Turned out Painter didn't like having the normal channel switched on for the Steel Rough material whilst having 'zero' as a value. Disabling the normal channel OR increasing the value solved the error. Very strange.
THIS CONTEST HAS ENDED. Winners will be announced July 12, 2010 with the Polycount Pack being released for Team Fortress 2 thereafter. To coincide with the launch of the new Polycount site, Polycount is teaming up with Valve Software to bring you the Team Fortress 2 Polycount Pack. Yes! That's right, an exclusive Polycount…