Hammer Editor Tutorial #25 - Portal 2 - How to make Doors - YouTube
An interesting little detail I noticed while exploring Portal 2's maps inside the Hammer editor. This test has a chamber that can be seen below, being moved along some rails. : r/Portal
Portal 2 Hammer Screenshot 2 by WarriorRazor on DeviantArt
Portal 2 Hammer Tutorial for Beginners | Part 2 - YouTube
Steam Community :: Guide :: p0rtalmaster's Hammer Guide Series Part 02/19
Portal 2 hammer- Behind The Scenes aesthetics tutorial - YouTube
Some Hammer-View Screenshots image - Portal Remake Mod for Portal 2 - Mod DB
Level Design Introduction/Getting Started (Portal 2) - Valve Developer Community