1. A system for generating a digital 3D model of an anatomical object including bone and cartilage based on predicting a shape of the anatomical object, the system comprising: a memory configured to store at least one database configured to store a first set of training models corresponding to bone models, a second set of training models corresponding to cartilage models, and a subject model corresponding to a bone model, wherein each model in the first set of training models corresponds to a model in the second set of training models, wherein the first set of training models and the subject model are characterized by a first parameter being bone, and wherein the second set of training models is characterized by a second parameter being cartilage; a processor configured to: determine an average shape for the first set of training models: determine a decomposition of the first set of training models; determine an average shape for the second set of training models; determine a decomposition of the second set of training models; determine a relationship between the first set of training models and the second set of training models as function of the average shape for the first set of training models, the decomposition of the first set of training models, the average shape for the second set of training models, and the decomposition of the second set of training models; determine a relationship between the subject model and the first set of training models; and generate the digital 3D model of the anatomical object based on a predicted shape of the anatomical object based on the relationship between the first set of training models and the second set of training models and on the relationship between the subject model and the first set of training models.