Fallout franchise started as an isometric RPG, way before it became a first person title we know today. Fallout 3 was the first game in the series to go full 3D, however, before the franchise was handed over to Bethesda, Black Isle Studios worked on two versions of Fallout games that were canceled.
The first iteration of canceled Fallout game was codenamed Van Buren that pops every now and then on the internet. However, for the second iteration of their game, Black Isle Studios decided to develop it in 3D.
Speaking with IGN, Obsidian CEO Fergus Urquhart shared some more details on the canceled Fallout games.
Now 3D was the cool stuff. So we were going to move from being a 2D engine and be a 3D engine, and so we actually started working with this 3D technology called NDL.
He added that the studio was making progress on the project but it was during the time of financial troubles for the studio. So instead of releasing Fallout 3, the project led to the creation of Icewind Dale.
According to Urquhart, he saw an opportunity to develop a dungeon-crawling RPG that would serve as an excellent “counterpoint” to Balder’s Gate, so “the Fallout 3 team became the Icewind Dale team.”
Urquhart noted that the 3D engine NDL they developed for the canceled Fallout game was bought by Gamebryo which was later used to develop Fallout 3 by Bethesda.