Ryzom

Mind you, if you have a legal question, you ought to consult a lawyer of your own to get actual legal advise. Shy of a few lawyers that might be reading this forum (likely to be none for some time) you aren't going to get any sort of legitimate legal advise and it is foolish to even try. A more proper way to phrase this is more like this:

If this model belongs to you and I decide to change the texture for a model, will you sue my ass off in court if I use a texture that has a different copyright license?

Even then, it doesn't address the legality of the issue, only the tendency that somebody will likely file a lawsuit. With all that, not I'm not a lawyer either, but I am somebody who has dealt with open source licenses quite a bit and has read them together with the philosophical ideas that underlie the licenses in the first place.

The general philosophy of open source content is that you should try to match licenses as often as you reasonably can, as mixing licenses creates a real harry legal mess that is best avoided when possible. Each type of content license has its own restrictions, and it very well may get you to the point that you will be forbidden to distribute whatever it is that you come up with.

Keep in mind, copyright applies to distribution of content, not to how you use it for your own personal use. So if you end up mixing up a Ryzom model with an image which you obtained from Microsoft under a Microsoft EULA, it may be "legal" for you to add that texture into that model, but the resulting model may only legally stay on your own hard drive and you can't share it with anybody else or legally put it into a video game that say a friend of yours wants to play.

Yeah, I know that doesn't answer the question directly, and even there the answer is "it depends".... just like everything else a real lawyer would tell you. Good luck with trying to get a clear and direct answer from anybody else on this topic too, at least if they are being honest. I would suggest that you try to avoid this situation if possible.

I am not lawyer but from what I read in creative common license any derivative must be also distributed under the same license.

So if you change Ryzom model by adding new texture it's still a Ryzom model with just a new texture so it's just derivative of the model and must be free to download.

But it does not mean you cannot sell it in the game shop.

You just must share with others so they can use Ryzom models with your textures too.

But RHorning is right, you should get lawyer to be sure.