Systems and methods for modifying three-dimensional digital items to fit different character models are described herein. In an embodiment a machine learning system is configured to compute a shape and size of three-dimensional digital objects to fit a second character model based on the shape and size that the same three-dimensional digital objects have to fit a first character model. A server computer receives particular input data defining a plurality of particular input vertices for a particular input three-dimensional digital object fit for the first character model. In response to receiving the particular input data, the server computer computes, using the machine learning system, particular output data defining a plurality of particular output vertices for a particular output three-dimensional digital object, the particular output three-dimensional digital object comprising the particular input three-dimensional digital object fit for the second character model. The server computer then causes displaying, on the client computing device, of the particular output three-dimensional digital object combined with the second character model.