Abstract: A 3D model system is configured to validate and optimize for 3D printing an unprocessed 3D model described by an input data file. The 3D model system is configured to detect printability issues associated with the unprocessed 3D model and automatically address these issues. Such issues can include boundary edges, non-manifold geometries, structural deficiencies, etc. Upon resolving these issues, the 3D model can be optimized for 3D printing. Optimizations can include hollowing to reduce printing cost and exterior surface smoothing. The resulting validated and optimized 3D model can be converted into an output data file which can be an input to a 3D printer or a 3D printing service for printing the object depicted by the 3D model. The 3D model system can operate as a network or cloud-based service. Users are able to interact with the 3D model system using a series of web-based user interfaces.