The free version of Epic Games' Unreal Engine 3 development kit (UDK) has been installed by over 800,000 game developers since its November 2009 launch.
That's according to Epic spokesman Mark Rein, who spoke to Gamasutra following his presentation at the Go Go Games Conference in the UK earlier this month. According to Rein, that figure represents the number of unique installations the company has seen since its launch a year and a half ago.
UDK is free to use, but operates on a revenue share model if employed for commercial products: when it was first launched, the terms saw Epic receiving twenty-five percent of a game's revenue after its first $5K was made. That threshold was raised to $50K earlier this year.
As part of his presentation at the British conference, Rein provided a sample of the terms a commercial developer might see.
In the example, a developer creates a game using UDK, and pays the upfront $99 fee to make it a commercial product. The developer goes on to sell 15,000 copies of the game at $4.99 each, for a total of $74,850. The hypothetical digital store takes a 30 percent cut, which puts revenues at $52,395.
As the initial $50K is royalty-free under UDK's current terms, Epic takes 25 percent of the remaining $2,395, or $598.75. Adding in the initial $99 licensing fee, Epic has collected $697.75 in this scenario, or 1 percent of the game's total retail sales.
UDK is available for consoles, PCs, iOS devices, and eventually, Android. It is not currently available for web browsers, but with Unity surpassing 500K users itself, it seems like a logical next step for the company -- though Rein wouldn't provide a comment for us.
In 2010, 65 percent of 3D game SKUs used Unreal according to Epic, citing a report from Acacia Research.