General Public License (GPL, or “free software”)

I’m not 100% sure how this licence works, but my main question is that am I able to download free 3D models under this licence and use them in my game. Also, I plan to sell my game commercially in the foreseeable future using the free 3D models I’ve download for free. I don’t know how to 3D model and all of the tutorials I’m finding are no help in me learning how to 3D model. That’s why I’m asking. Please and Thank You!

The UE4 EULA does not permit use of GPL licensed content in connection with the engine. Specifically:

You may not combine, Distribute, or otherwise use the Licensed Technology with any code or other content which is covered by a license that would directly or indirectly require that all or part of the Licensed Technology be governed under any terms other than those of this Agreement (“Non-Compatible License”). Code or content under the following licenses, for example, are prohibited: GNU General Public License (GPL), Lesser GPL (LGPL) (unless you are merely dynamically linking a shared library), or Creative Commons Attribution-ShareAlike License. Code or content under the following licenses, for example, are allowed: BSD License, MIT License, Microsoft Public License, or Apache License. You may not sublicense the Licensed Technology under a Non-Compatible License.

So the way I’m understanding is that I can not use non-compatible licenses for commercial use because they go against the Unreal Engine 4 licenses, but I am allowed to use the compatible licenses for commercial use in the Unreal Engine 4?

If possible, could someone post a link where I am able to use 3D models for commercial use and able to use it alongside Unreal Engine 4. Again, I can’t 3D model so this is very helpful. Please and Thank You!!

I appreciate you taking the time to get back to me, thank you!

You’re correct, although the commercial use part isn’t relevant. You’re allowed to use compatible licenses with UE4, but not non-compatible licenses.

I don’t think I would need to open up a new question for this, so I’m going to ask hee. Would anything under the Public Domain be compatible?

Technically, public domain isn’t licensed so it’s not a question of a compatible or non-compatible license; but it would be ok to use. But note that there is a lot of misconception about what constitutes public domain - certainly not just because something is available online without a license.

CC0 is the closest thing that exists to a public domain “license” and that is compatible.

“Creative Commons Attribution 3.0 License” is not the same as “Creative Commons Attribution-ShareAlike License” ?

No they are not the same. CC-Attribution only requires you to give credit where credit is due. CC-ShareAlike requires you to provide that license which entitles those you Share the content with, base code and/or original editable content. Putting content in your Unreal Engine game that is of the license CC-ShareAlike would then require you to offer all your code (technically Epic’s code to the engine) free to use to whomever downloads your content under that license.

While Epic gives us and virtually anyone free access to their code for the engine, they want the power to exercise their rights to decide who gets it and the ability to track who uses it. Anyone who uses the engine must agree to the EULA - giving the code out under a CC-ShareAlike bypasses the requirements for people to agree to the EULA.

Ok, it is allowed to use LGPL/GPL as long as we link dynamically. But are we allowed to ship the dynamic library with the game? When we ship it with the game, I would consider it part of the game and thus the whole game whould be part of LGPL/GPL which is not allowed.

Means: Can we ship the dynamically linked library under LGPL with the game when the library is publically available after installation (not merged into a package after game installation)?

As an initial point, the GPL cannot be used with UE, regardless of whether the GPL-licensed code is dynamically or statically linked. The GLP is a “Non-Compatible License” under Section 1(B)(ii) of the EULA.

That being said, it’s OK to ship an LGPL-licensed library with your game, so long as it is only dynamically linked to your game.

Thanks for your reply DudleyStephens. Realy appreciated. I have another question I hope you can help with. I realy don’t want to violate any rights. But the field of licensing is to big and there are to much small gaps.

What about shipping a GPL licensed software with the Game? The Game itself does not link to that GPL software in any kind of way. The Game only makes a call to the GPL software at somepoint. Is that ok?

I’m Epic’s attorney, so I can’t advise you on the interpretation of the GPL.

I will note that the relevant restriction in the UE EULA is as follows:

You may not combine, Distribute, or
otherwise use the Licensed Technology
with any code or other content which
is covered by a license that would
directly or indirectly require that
all or part of the Licensed Technology
be governed under any terms other than
those of this Agreement
(“Non-Compatible License”).

This means that as long as your use of GPL-licensed code doesn’t violate that provision, it is OK with Epic. This becomes a fact specific question, but a possible example of such use would be a server that uses some GPL-licensed code (but does not use UE) and a client that uses no GPL-licensed code at all, but does use UE.