Unreal Engine 4, the latest version of the game engine developed by Epic Games, is now completely free for anyone to use, the company announced today.

Epic originally launched Unreal Engine 4 in March 2014 for "early adopters" with a subscription model, charging $19 per month plus a royalty fee of 5 percent on sales. Previous iterations of the Unreal Engine had been directed at large development teams making big-budget games, with costly licensing fees associated with the technology. Epic said at the time that it wanted to open up Unreal Engine 4 to a wider audience.

"The state of Unreal is strong, and we've realized that as we take away barriers, more people are able to fulfill their creative visions and shape the future of the medium we love. That's why we're taking away the last barrier to entry, and going free," said Tim Sweeney, founder and CEO of Epic Games, in a post on the Unreal Engine blog today.

Unreal Engine 4 is now free to download, and all future updates will also be free. Developers of commercially released games or applications will pay Epic a 5 percent royalty on gross revenue above $3,000 per product, per quarter. Gamasutra reports that larger studios can continue to negotiate deals with Epic that reduce or don't involve royalty payments.

"It's a simple arrangement in which we succeed only when you succeed," said Sweeney.

The free software is Unreal Engine 4 in its entirety, the full C++ source code, and supports Windows PC, Mac OS X, Android, iOS, virtual reality (Oculus Rift and Gear VR), Linux, SteamOS and HTML5. Registered developers for PlayStation 4 and Xbox One can use those platforms as well.

Epic will be issuing a prorated refund to people who have paid for Unreal Engine 4 since Jan. 31. In addition, anyone who has ever subscribed will receive a $30 credit for the Unreal Engine Marketplace. For more on Unreal Engine 4, check out the trailer below, which Epic released today.