If you buy the royalty free rights to use/edit a 3d model and textures in "any commercial software or application you develop", so long as the buyer doesn't have access to the model(must release as exe, apk, etc), and you can't resell the models on a competing website.
There is no mention of 2d derived art in the terms of use, what happens if you make an application that people will screenshot arrangements of your 3d model? Say for a background, or you let them position things to make their own themed image and print it?
Now say that application is a sprite sheet generator that has 3d animated models that snaps a sequence of screenshots at different poses, lines them up, resizes and packs into a png file....hence a generator.
Technically it's a standalone application and the users don't have access to the models without breaking the law. It's not in direct competition because the modeler doesn't sell 2d art in any way.
So I'm wondering both since I've already bought tons of models, but also when I buy in the future what must I verify in the terms before buying to include them in an application like this? What should I verify with the models I've already bought? I think if you ask an artist "can I do this", they'll obviously want more money, but they write the terms of use and it didn't specify anything about 2d art, only the 3d models.
How would you approach artists for models you've already bought? Would you restate to them that their terms didn't mention 2d art, then tell them about your app, or what? They don't even list the terms anymore on their site, I have a 3+ year old version but there's currently no terms listed when you buy models.