We are a 3D printing service that requires some changes in models (STL or OBJ), normally humans that need to change the position of the legs and arms, and general changes. We also need to build cars and other models from a picture.
Sometimes we need an entire model brand new, right now we need a real look model of the world champion Ayrton Senna.
Normally our models are with limited production and had serial numbers to keep the price up.
We have work on a regular basis and we can discuss the royalties and the compensation. We can agree on a price plus royalties, only price, and only royalties. We want a long term relationship.