1. A system to improve output operation of a 3D printer including a system for automated metrology, measurement, and model correction of a three dimensional (3D) model to ensure 3D printability and manufacturability of the 3D model as a physical object, said system comprising: at least one processor configured to: simulate an actual 3D printing process of the 3D model to generate a layered simulated 3D model describing the 3D model as it is to be printed, wherein operations to simulate the actual 3D printing process of the 3D model includes global model correction and local model correction being available; receive or generate slices of the 3D model, the slices representing two dimensional (2D) solids of the 3D model to be printed in corresponding print layers; calculate medial axis transforms of the slices, the medial axis transforms representing the slices in terms of corresponding medial axes, wherein a medial axis transform is a representation of a shape in terms of a lower dimensional medial axis that represents a focus of centers of maximal inscribed discs that are completely contained inside the shape, a medial axis topologically equivalent to the shape, and a local feature size at a point “x” on a boundary of the shape is thus the radius of the disc that is tangent to the shape at “x”; determine the local feature size at any point along the boundary of the slices as the shortest distance from the point to a corresponding medial axis, wherein the local feature size defined in terms of the medial axis transform is used to automatically identify regions that require a differential addition of material to ensure manufacturability at regions including at least one of walls, bridges, protrusions, and holes, and wherein topological consistency between parts of the 3D model before and after manufacture is maintained; generate a visual rendering of the layered simulated 3D model; display the visual rendering of the layered 3D model on a display device; and control a 3D printer to physically print the 3D model according to the layered simulated 3D model.