Is it legal to use parts of someon’s else models to create models?
For example:
I wanna create human with horse head.
I find and dowmload models of horse and man.
Cut horse body, remain only horse head.
Then bridge horse head with man model and edit in zbrush.
Create new wireframe? higp poly model with details.
Is It legal?
It depends on the license of the original model you were using.
Example … a Free Horse Model and a Free Human Model that states it can’t be used commercially or has to be used Open Source … then NO. You would be infringing their license and copyright.
If you bought the models or you were granted a commercial use or non-restricted license then you could chop and change as you see fit. However you might still hit issues if the license says no reverse engineering or if you try to sell it off as your own model (i.e. not in a game but as an asset).
I generally will buy assets commercially and modify them to my needs but they always stay in the game and I never release them as separate assets.
When in doubt … contact the author of the models in question directly … rather safe than sorry IMHO.
Unless they specifically state that you’re allowed to use their model, you’re not allowed to.
It all depends on the context of the usage. You should probably look at Derivative work - Wikipedia and Fair use - Wikipedia. You should also address the look and feel, a design patent can protect the appearance of an entity
An additional part of the conundrum is the licensing issues. Some products have may have external constraints to the usage of the product being used in a commercial product.
There is also the ethical nature of using somebody’s work with out payment or credit.
For the horse and man example. you cant copywrite or patent generic examples of either (fair use). If either is stylistically unique then the models should probably not be used. If the man is riding the horse (or vice versa), that is not unique and whatever licenses should be followed. If you modify the man and the horse by more than 75 to 80% than that is generally considered a unique derivative (as long as it doesnt violate look and feel). Merging the two and creating a centaur does not make a derivative greater than 75 % of both models(the man would be 50% and the horse would be less). But by modifying the skins by more than 80%, adding a bone structure, and animating it. The new entity is now a unique creation, even though it is a derivative work.