Capstone Software was a subsidiary of IntraCorp, a Miami-based computer and video game company. Founded in 1984, Capstone created first-person games such as Corridor 7: Alien Invasion, William Shatner's TekWar and Witchaven, and is also known for releasing games based on movie/TV licenses. Capstone's first-person games used the Wolfenstein 3D engine, and later, the Build engine (best known for powering 3D Realms' Duke Nukem 3D).