http://udn.epicgames.com/Three/ChangingUnits.html In the end: "UE3 treats one Max Unit as one Unreal Unit, regardless of what length the units were originally set to in Max." Not sure about that, but to me, it looks like this: wether you're modeling with centimeter/feet or whatever, in the end, UDK will read 1cm=1UU=1foot=…