License discussion (NC and not NC )

[Omega]

If someone builds a new mod using one of your models he cannot use a model from MG iitself or another mod because this results in a license conflict.
So making a new tileset using tree models from your mod and tree models from original MG will not be allowed.

This is not true. You can license specific things under different licenses. So you can have some models under CC-BY-SA and others under CC-BY-NC-SA. You simply have to specify this somewhere (eg, in a "LICENSE" file). What you can't do is just claim the whole mod is one license when there's actually mixed assets. Although you can do that if the licenses are compatible, but judging compatibility is difficult. For example, the GPL is a CC-BY-SA compatible license. But to make things even more confusing, CC-BY-SA is NOT a GPL compatible license (ie, it's one way). So best to never try and relicense. Just keep track of the individual licenses and ensure that modifications to the media follow the license.

[titi]

This is not correct, CC-BY-SA forces you to release a derived work under the same license. Same does CC-BY-SA-NC . so combining them in a mod means you have a derived work form those two things which is your new mod. But this mod can either be CC-BY-SA or CC-BY-SA-NC .
If it would be like you say, it would be possible to create a commercial game using CC-BY-SA-NC art, just by saying hey, this one model is  under CC-BY-SA-NC license. This is not possible and its against the intention of those licenses too.
And that's exactly what happens then you mix CC-BY-SA and CC-BY-SA-NC. You are allowed to sell CC-BY-SA things , but you are not allowed to sell CC-BY-SA-NC.
And if you say hey, I release all with CC-BY-SA-NC you relicense the art which was CC-BY-SA before with somehting which is not allowed to be used Commercially.

Some people might do this, but as far as I know mixing is not a legal thing.
Like GPL licenses for code, CC-BY-SA is a license for art that can only be used in a new creation which has the same license.

update: see here and especially notice the license table: https://wiki.creativecommons.org/wiki/Frequently_Asked_Questions#When_is_my_use_considered_an_adaptation.3F

[Omega]

You misunderstand the granularity of which I use "work". You seem to be thinking of saying "this mod is CC-BY-SA". But I'm thinking at a lower level, such as "this mod contains models that are CC-BY-SA and other models that are CC-BY-NC-SA".

[John.d.h]

To the best of my knowledge, what exactly constitutes a monolithic work vs. a "mere aggregation" of smaller works (like an album) is not well-defined.

[titi]

Well it may not be well defined, but if you release something combined in one archive, give it a name and so on I am quite sure this is a "monolitic work" and not just a collection of art. The xmls combine the mod to one monolitic thing and I bet every lawyer will make you pay :-/ . Here in germany I would not dare to do something like this.

[titi]

I opened a discussion on http://forum.freegamedev.net/viewtopic.php?f=7&t=6668
If possible lets discuss there, as there are more poeple with knowledge.

[Ishmaru]

Legal or not, from my experience with Annex I highly recommend NOT using assets of varying licenses. It can quickly become a headache when it comes to promoting, distributing, and porting your mod. Several times I had to re-licence/replace assets to distribute Annex for different platforms.

[John.d.h]

Well it may not be well defined, but if you release something combined in one archive, give it a name and so on I am quite sure this is a "monolitic work" and not just a collection of art. The xmls combine the mod to one monolitic thing and I bet every lawyer will make you pay :-/ . Here in germany I would not dare to do something like this.

I see what you mean, and I generally prefer to act on the side of caution as well.

[filux]

So basically summing up a bit (in my opinion):
1. NC shouldn't be included into "basic data".
2. If/when we have NC in the mods' center then this always should looks like:
- all .xml as CC-BY-SA
- some models and textures may be as NC.

Additionally we should have some clause like e.g. "authors agree that all NC content after a year in the mods' centre will be automatically relicensed to CC-BY-SA".
By this authors will be happy by protection of their "fresh hard work" and you will be able to include some parts of this to "basic data" after some known time.