Unreal Development Kit - Epic Games
What is UDK? The Unreal Development Kit is the free edition of Unreal Engine 3 that provides access to the award-winning 3D game engine and professional toolset used in blockbuster video game development, architectural visualization, mobile game development, 3D rendering, digital films and more. Who is it for? Unreal Engine technology is used by game developers, researchers, television studios, machinima directors, artists and students. If you have an idea that needs to be brought to life in a game engine, you might consider UDK. Using UDK you can deploy games and applications to PC, iOS and Mac. Note: We recommend folks starting new projects to give Unreal Engine 4 a try!