Though many users prefer to use external modeling programs, the model editor (or MED for short), gives you the capabilities to design models, and is sometimes used to make levels. Models can be made of anything ranging from simple boxes, to human models or complex environments like an entire city. Models are made of meshes, a group of vertices and triangles (often called "polygons") put together to form a shape; a skeleton of bones for animation; one or several textures for the skin; and effect files (.fx) for shaders.