What is the difference between solid, semi solid and non-solid brushes?
Solids are just that. Semi-solids are like solds but don’t make poly cuts into Solids. They do make cuts into each other though. Also they have a bad tendacy to cause collision errors in the map if they are often within the players touching range. They can also be used for decorational objects to avoid BSP holes. Non-solids are just that. Brushes that can be walked through. There can be some interesting uses for these.