It did, and Bethesda had time to iron out the kinks in the code that Obsidian used. But Fallout 3 used the 3rd party Gamebryo engine anyway, so the engine wasn

It did, and Bethesda had time to iron out the kinks in the code that Obsidian used. But Fallout 3 used the 3rd party Gamebryo engine anyway, so the engine wasn't really developed by Bethesda either.