Props help to decorate the world. They take less computer power to render and simulate than world geometry, but you need third-party software in order to create them. All props are point entities and are placed into the map with the entity tool.
Most of the props used in a Source map are static props. Static props account for any nonmoving (static) object. Light posts, wall clocks, trees, and pipes are all examples of items that can be static props. Let's place a tree on the dirt mound we have just created.
In the Objects drop-down, select prop_static and then left-click on the dirt mound in the 3D window to place a prop_static entity. It will be displayed as a red box. Left-click on it twice or hit Alt + Enter to bring up the object properties. In order to define which model we want to use for the prop, select the World model property, and click on browse to bring up the Model Browser window.
The model browser allows you to filter and search for all the...