Modifying or “modding” a video game has become a popular pastime for many gamers over the last few decades—skillfully taking an existing game and changing it into something new. These changes can be as simple as altering a character’s appearance to completely swapping out the assets to create a whole new game altogether. Some of today’s most popular games started as mods, chief among them being Counter-Strike and Dota, and both were acquired by Valve and turned into extremely successful standalone games. Modding keeps a game fluid and relevant, so it’s no wonder that many developers have harnessed this creative community to their advantage.

Rockstar is still rockin’ it with Grand Theft Auto V due to a never-ending realm of possibilities in the game’s open world but also due to creative mods from its fans. These mods range from homemade missions to absurd characters and vehicles—as fun to watch as they are to play. Rockstar will periodically host live gameplay sessions, highlighting fan creations in GTA V as experienced by popular YouTube personalities.

Minecraft is another highly popular game for mods, creating custom worlds and adventures for themselves or the enjoyment of millions of subscribers. Like GTA V, these mods create endless entertainment possibilities for players and those who stream online—helping to sell over 121 million copies. The game is used in classrooms, teaches problem-solving skills and is even being used for eSports, thanks to organizations like Super League Gaming.

Epic Games has a long history of supporting game mods by offers tools through its Unreal Engine (UE) to modify several games like Unreal Tournament and Studio Wildcard’s ARK: Survival Evolved. The company even offers UE4 tutorials to help players learn to mod its games.

“This goes back to when Epic Games first introduced the editor and modding tools to the community,” Stacey Conley, community manager for Unreal Tournament told [a]listdaily. “Some people were able to grasp the concepts around using the editor, but many had the desire to create but did not understand the tools. Unreal Editor communities started popping up and people started asking questions. The more knowledgeable members starting creating tutorials and sharing assets. The community thrived! Some of the people creating and using the community tutorials now work for Epic. They benefited from the tutorials in a big way and they want to be sure that people using Unreal Engine and our game modding tools have the same benefit. It’s a labor of love. The modding community has always been known for its goodwill and generosity. On top of that, we’re now seeing a number of mod editors built on Unreal Engine 4 being released on the Epic Games launcher. We’ve been building and releasing learning resources for UE4 for more than three years now, and new communities of modders are able to grow their skills from the large pool of tutorials and documentation that’s out there.”

Modding has made Epic “much more community-oriented on the development side,” Conley explained, saying that they take particular care to help their players succeed in their creative goals. After all, she said, modding offers players “the world.”

“You not only shape the game that you want to play, but you can change the visual style, add new weapons, and even make a whole new game,” Conley said. “There is no limit to what you can do. Modding also offers a sense of community to those who love games, and are interested in how they are made, learning by using actual development tools like Unreal Engine 4. Teams form, and some go on to create their own games. Some of the most successful games out there started as mods for other games. Rocket League, for example, came out of popular Unreal Tournament mods!”

“We are in the unique position of not only having gamers following us, we also have modders and licensees watching our streams for information,” she explained. “This cross-pollination lends itself well to streaming and our Unreal Engine stream is watched by people at both ends of the spectrum. People will watch our game streams to see a new feature in our games. The modders who watched will jump to an Engine stream to see how it was done. In turn, they will be guided to someone streaming workflow or even stream themselves. We also host streams of creatives, gamers and modders on our channels. We’re very happy to see more and more developers streaming their work and sharing their knowledge.”