Systems and methods are disclosed for fitting a subject by generating one or more 3D deformable models for an anatomical portion; capturing images of a user anatomical portion and a reference object using a mobile camera; generating an updated model of the user anatomical portion by selecting a closest 3D deformable model to the user anatomical portion and matching points on the closest 3D deformable model to one or more predetermined points on the user anatomical portion; and selecting a best-fit product from a plurality of product variations based on the 3D model.