Models not made by Zygote/Daz3d are each different in how the owner of the copyright feels on derivative work. You have to contact the owner of the copyright to be sure before proceeding :) For instance, the items sold in the store here... by the license you are not allowed to create and remarket derivatives off them, even though they first originated themselves as Daz3d work. I know that may not make sense, but it is like this, Daz says it is ok to make derivatives of their work, but the copyright owners who then did, do NOT say it is ok to make derivatives of their work... at least not in a blanket sense. So contact every single person whose work you wish to work off of, to be safe :) Better safe than sorry... better safe than flamed ;p