If you followed our first Source SDK tutorial, you should have gotten to grips with the basic features of Hammer: you can use brushes to create rooms and corridors, change textures and place props. Your level is still mostly lifeless though, so it’s time to use Triggers to make things happen.

Get your freaky-stick-with-eyes and magic fairy dust out; it’s mine cleaning time. The Techies are here, and ready to cover the forest and lane with your giblets!