UDK meaning in Community ?

Unreal Engine is a game engine developed by Epic Games, first showcased in the 1998 first-person shooter game Unreal. Initially developed for PC first-person shooters, it has since been used in a variety of genres of three-dimensional (3D) games and has seen adoption by other industries, most notably the film and television industry. Written in C++, the Unreal Engine features a high degree of portability, supporting a wide range of desktop, mobile, console and virtual reality platforms.

The latest generation is Unreal Engine 4, which was launched in 2014 under a subscription model. Since 2015, it can be downloaded for free, with its source code available on a GitHub private repository. Epic allows for its use in commercial products based on a royalty model, typically asking developers for 5% of revenues from sales, though Epic waives this fee for developers that publish their games through the Epic Games Store. On May 13, 2020, Epic announced that their portion of royalties for games developed in Unreal Engine are waived until developers have earned their first US$1 million in revenue, retroactively applying to January 1, 2020. Unreal Engine 5 is scheduled for full release in early 2022.

It is popular among PC and console games with high graphics capabilities and is used for numerous games, as well as finding further use in filmmaking and other business applications.