Its virtual sets were generated with an Unreal Engine 3-based framework, created by Raymond P. Le Gué and known as XRGen4. According to Le Gué, "We start with the live actors and puppets on a physical set with a green screen behind them as a backdrop. The green screen is replaced in real time with the sets created in XRGen4 using UE3. As we move the camera and actors around the physical set, the backdrop scene also moves in real time in complete synchronization with the movements of the real camera. All of this is recorded, and the director can watch the resulting composition in real time." Seasons 3 and 4 of "LazyTown" were filmed as usual in the LazyTown Studios in Iceland, but the special effects were created this time round by Turner Studios in Atlanta.