A cancelled Fallout 3 project is responsible for Icewind Dale, says Obsidian CEO

Separate from Van Buren.

Back when Interplay and Black Isle Studios were still making Fallout games—prior to Bethesda's acquisition of the series—"Van Buren" was the codename given to an ill-fated unreleased turn-based version of Fallout 3 that long predated the three-dimensional open-world game launched in 2008. What you may not know is that 2000's D&D-inspired role-player Icewind Dale also began life as a 3D take on the post-apocalyptic wasteland in a bid to serve as a counterpoint to Baldur's Gate. 

That's according to Obsidian CEO Feargus Urquhart, who, in conversation with IGN, explains that prior to working on Van Buren Black Isle Studios also worked on a different version of Fallout 3—immediately following Fallout 2, while Planescape: Torment was still in the works. 

"It was actually the second Fallout 3," says Urquhart of Van Buren, suggesting that the decision to make Fallout 3 three-dimensional wasn't necessarily first thought of years later. "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."

Interplay's well-documented financial bother ultimately led the Californian publisher to capitalise on Baldur's Gate's popularity, as it changed the direction of the proposed Fallout 2 follow-up and instead began crafting a dungeon-crawling RPG. "The Fallout 3 team became the Icewind Dale team," adds Urquhart. 

And the rest is history, so goes the well-worn cliche. Interestingly, Urquhart says the aforementioned NDL technology was purchased by Gamebryo, who ultimately powered Betheda's version of Fallout 3 years later.