To remove the HUD in Battlefield 3, use the new console command “UI.Drawenable 0“.

I can see how this can be useful for making nice community videos and such, especially when DICE release the Battlerecorder for Battlefield 3 – yes, due to popular demand, DICE are said to actually be working on it, however no official information has been given yet about when it will be made available.

Also, check out this Battlefield 3 Wake Island easter egg by