Epic has just told Develop that the UDK, its free version of the Unreal Engine 3, has been installed over 50,000 times since its release.
The development kit, which is free for non-commercial use with a royalty sharing option available for those wishing to make money from their creations, was unveiled last week in a surprise move by the engine firm.
According to the firm, those 50,000 users are spread around 130 countries and 4,500 cities across the world.
The UDK features the much-lauded UE3 toolset, including level editor, particle editor, Matinee cutscene creator, and Unreal Content Browser, but currently can only be used to create PC titles.
"We are very excited to see the uptake of UDK cross over the 50,000 mark in only one week, and we're looking forward to seeing amazing games and applications come out of it," said Mark Rein, vice president of Epic Games.
"We're also thrilled to finally be able to offer UDK free for schools and students so they can work with the same awesome Unreal Engine 3 tools used by many of the top game developers and publishers around the world."
3DBuzz, long-term training supporter of the Unreal Engine, has also announced that it will soon release 'dozens' of free videos specific to UDK, in addition to the 100+ free Unreal Technology video tutorials it already hosts.