License to Mod

Steam will be a huge target for this engine, so I figure lets get some of the License questions out of the way. Steam is a community based on modding games. Valve’s Gold Src, Source, and now Source 2 that runs DOTA 2 all hugely support modding, Counter Strike, Team Fortess etc. are just a few that have tons of work in the Workshop category.

Can we distribute the source of this engine/framework with our game?
I am new to MPL 2. Say we decided to use Armory for our game. The great thing about Steam is they have Blender as an app. So it would be really easy, and all included in one platform to have the potential modder download blender, then download a workshop item or a zip containing the source, then just have them open blender and point user prefs to where the is.

The downside of this is you don’t have the blender player which aids in rapid development. In turn I wonder if we could include the blender source in workshop as well and just give instruction on how to build from source as a method 2.

Either way, locking in the details of what is okay and not okay, in plain language, would be great. I think this would be a great solution to Steam games that want to allow modding of their games, can we include the source and link to the git repo/MPL license and be good?

I did some checking:

Q9: I want to distribute (outside my organization) MPL-licensed source code that I have modified. What do I have to do?

To see the complete set of requirements, read the license. However, generally:
You must inform the recipients that the source code is made available to them under the terms of the MPL (Section 3.1), including any Modifications (as defined in Section 1.10) that you have created.
You must make the grants described in Section 2 of the license.
You must respect the restrictions on removing or altering notices in the source code (Section 3.4).

…this seems to say it is okay, I am just double checking that I am understanding it correctly and wanting to get the communities take on this.

1.10. “Modifications”

means any of the following:

(a) any file in Source Code Form that results from an addition to,

    deletion from, or modification of the contents of Covered

    Software; or

(b) any new file in Source Code Form that contains any Covered

  1. License Grants and Conditions

2.1. Grants

Each Contributor hereby grants You a world-wide, royalty-free,

non-exclusive license:

(a) under intellectual property rights (other than patent or trademark)

Licensable by such Contributor to use, reproduce, make available,

modify, display, perform, distribute, and otherwise exploit its

Contributions, either on an unmodified basis, with Modifications, or

as part of a Larger Work; and

(b) under Patent Claims of such Contributor to make, use, sell, offer

for sale, have made, import, and otherwise transfer either its

Contributions or its Contributor Version.

2.2. Effective Date

The licenses granted in Section 2.1 with respect to any Contribution

become effective for each Contribution on the date the Contributor first

distributes such Contribution.

2.3. Limitations on Grant Scope

The licenses granted in this Section 2 are the only rights granted under

this License. No additional rights or licenses will be implied from the

distribution or licensing of Covered Software under this License.

Notwithstanding Section 2.1(b) above, no patent license is granted by a


(a) for any code that a Contributor has removed from Covered Software;


(b) for infringements caused by: (i) Your and any other third party’s

modifications of Covered Software, or (ii) the combination of its

Contributions with other software (except as part of its Contributor

Version); or

© under Patent Claims infringed by Covered Software in the absence of

its Contributions.

This License does not grant any rights in the trademarks, service marks,

or logos of any Contributor (except as may be necessary to comply with

the notice requirements in Section 3.4).

2.4. Subsequent Licenses

No Contributor makes additional grants as a result of Your choice to

distribute the Covered Software under a subsequent version of this

License (see Section 10.2) or under the terms of a Secondary License (if

permitted under the terms of Section 3.3).

2.5. Representation

Each Contributor represents that the Contributor believes its

Contributions are its original creation(s) or it has sufficient rights

to grant the rights to its Contributions conveyed by this License.

2.6. Fair Use

This License is not intended to limit any rights You have under

applicable copyright doctrines of fair use, fair dealing, or other


2.7. Conditions

Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted

in Section 2.1.

  1. Responsibilities

3.1. Distribution of Source Form

All distribution of Covered Software in Source Code Form, including any

Modifications that You create or to which You contribute, must be under

the terms of this License. You must inform recipients that the Source

Code Form of the Covered Software is governed by the terms of this

License, and how they can obtain a copy of this License. You may not

attempt to alter or restrict the recipients’ rights in the Source Code


3.4. Notices

You may not remove or alter the substance of any license notices

(including copyright notices, patent notices, disclaimers of warranty,

or limitations of liability) contained within the Source Code Form of

the Covered Software, except that You may alter any license notices to

the extent required to remedy known factual inaccuracies.

I AM NOT A LAWYER, and also I am just a user who can’t speak for Lubos’s intentions, but:

Should explain things fairly simply.

Also, in order to distribute Blender’s binaries you must comply with the GPL which Blender is licensed under:

thanks seems pretty clear that it is allowed. one new thing I found out is that with blender I can use the blender trademark, but with Armory license I cannot.

Should be good! If there would be license issues regarding this then we will resolve that, as this is potentially another cool use-case.

As for the license intentions - if someone decides to fork engine for it’s own needs (perfectly valid), then it is required to make engine changes open-source so everyone can benefit from that. Apart from that I would like to prevent any crazy limitations. :slight_smile: