Can i make another engine from ue4 source?

I want to know if its possible to modify ue4 source to create another engine, not a game, but another software using the entire engine (the editor, lightmass). Example: A Home Designer software that uses unreal editor and bsp to create the house and lightmass to generate the lights, but removing other things that is not needed, making the editor more user friendly.

The license does not permit shipping a product that was compiled from any code derived from the editor. In practical terms, only code under the /Engine/Source/Runtime/ as well as built-in “Runtime”-type plugin modules are allowed to be used for your product. You can customize the editor code and features all you want for your development needs, but you aren’t allowed to create a shipping product derived from the editor or auxiliary tools like Lightmass.

That said, Epic is a huge proponent of “moddable” games and we want developers to be able to ship tools for their customers to extend and edit UE4 products. You might want to check out this thread for some insight from Tim and others on this topic.


thanks for clarifying me, it is possible to use lightmass in runtime? to generate lightmaps, like if i create an level editor for my “game” and want to generate lightmaps.

I doubt we would do this anytime soon. Lightmass is an offline baking tool that works best with UnrealSwarm (to make use of many CPU cores across many computers). It isn’t designed to be a good experience for a runtime user application. Unfortunately I think your application isn’t a great fit for the current license, but you should keep an eye on eventual announcements from Epic about modding support and the ability to release your own editing tools. Or you can get in contract with us directly and try to work something out.