The Terrain Entity
The process of building a piece of terrain focuses on a new thing called the “Terrain Entity.” Technically speaking, the terrain in Team Arena is nothing more than a func_group entity (brushes only) with a number of key/value pair combinations that are unique to it. These key/value pairs define it as terrain (terrain), establish the piece of art that will be used to locate textures on it the terrain (alphamap), define the group of shaders used to blend textures across its surface (shader), and tell how many different unique shaders will be used. The bsp-making utility, Q3Map compiles and textures the terrain entity based on the parameters specified in those key/value pairs.
It is possible to have multiple terrain entities in a map (see Terrain Entities below). Once you learn the method and the techniques, terrain is relatively easy to create. One warning though … easy to create does not mean easy to compile. Large maps take a much longer time to compile, and huge maps are likely to take what seems like forever. However, there are some construction, lighting, and shader options that can significantly cut down on compile time - as will be noted later.