Hammer Editor - Tutorial 7: Skybox and 3D Skybox - YouTube
J.A.C.K. on Steam
How to Optimize a Map in Hammer Editor: 10 Steps (with Pictures)
I was using the hammer editor and noticed that ragdolls eyes stare at you all the time and its so creepy i kinda wanna stop messing with this map for now :
Introduction to Hammer Editor and Mapping [Counter-Strike 1.6] [Tutorials]
Hammer Object Properties-Dialog (Objekteigenschaften) - Valve Developer Community
How to Optimize a Map in Hammer Editor: 10 Steps (with Pictures)
Simplici7y - Hammer editor Pfhactory N Utopia by ZipZap2