Unreal Development Kit
The Unreal Engine Development Kit is a special runtime version of the Unreal Engine designed to meet unique needs of independent game developers and non-traditional 3D visualization projects.
Unreal Development Kit (UDK).
Based on Unreal Engine 3.
Use of the UDK for noncommercial purposes is free of charge. If you are going to use the UDK for any commercial purpose or in any way that is not specifically authorized in the end-user license agreement (EULA), you must agree to appropriate commercial terms. You can read more about these options at http://udk.com/licensing
