There's an interview with Tim Cain on Duck and Cover talking with the Design Director at Carbine Studios looking back at his days at Interplay and Troika Studios. One of his answers is a description of a post-apocalyptic game they were planning at Troika: "We had begun the development of a really interesting take on the post apocalyptic genre. The background was about as different from Fallout that you could get while looking a great deal like that game. We had made our own modern 3D engine to drive it, complete with real-time shadows and incredibly smooth character animation. Jason, Leonard and I wrote a background and system specification that would have made for a very rich game world to set adventures in, but we never found a publisher that was interested."