3MF is a new 3D printing format that will allow design applications to send full-fidelity 3D models to a mix of other applications, platforms, services and printers.
3MF is an XML-based data format – human-readable compressed XML — that includes definitions for data related to 3D manufacturing, including third-party extensibility for custom data.
The code to read or write 3MF is available as open source: Microsoft’s donated code reads STL/OBJ/3MF, writes 3MF, and can use Web Services for model repair.
The 3MF format is designed to be an additive manufacturing format, with the complete model information contained within a single archive: mesh, textures, materials, colors and print ticket. 3MF provides a clear definition of manifoldness — open source code available for rapid validation and there is no ambiguity for models with self-intersections.