I don't care about patents, just do what you like, if they sue, then there idiots.A lot of small software companies aren't going to think like that, nor are, say, Open Source developers. PHP? Apache? SQL? Where'd TWHL go all of a sudden?
...which I think appeared in the very best moment to uproar the American people. In this forum, there's a thread about it, which shows how easy people can change their oppinion after one single thing.Hm, I must say that's true. If these supposed-arabs (I don't know who they perpetrate to be) are trying to get us away, they certainly timed it poorly.
In Halflife, brushes are required to have all faces be of the same type (solid, water, slime, sky, origin). Fortunately almost all textures are solid. If you put a water texture on one side of a brush which has dirt or steel textures for example, that would generate the error. The engine needs to know what is inside the brush, and it would be real confusing if different types could be put onto the same brush.
The fix is relatively simple. Simply find the offending brush, and then the faces with the inappropriate texture and change it. If a brush uses SKY, all sides must be sky. The same is true for CLIP, and ORIGIN textures as well. If you are careful it is possible to mix water textures (provided you don't accidently use a slime texture on the brush)