Nice looking rendering! --If I understand that you are NOT selling 3D models- but artwork-illustrations- I don't think you have a copyright problem to worry about. It can become a little bit more difficult if a specific image became widely used to promote a major product- or was used in a movie scene. In that case you would need to make sure all your bases were covered legally. That would be because if a LOT of people were seeing the artwork (like millions) and someone could identify it as THEIR design you used- and you didn't have a copyright release- THEN that could be a problem for you.