Microsoft is partnering with Makerbot to provide native support for 3D printing in Windows 8.1, including an API for developers, an improved data format, and standardized printing dialogs.
[Microsoft is] defining a standardized feature set that represents what current and future printers can and will do, for one. Microsoft is also pushing for the use of its own 3D data format (3MF) that addresses the current’s (STL) shortcomings — most notably its lack of support for different colors and materials
Gavin Gear gives an overview of 3D printing support in Windows 8.1 and a demo of printing a 3D object from a Windows Store app to a 3D Systems Cube 2 printer using Windows 8.1 Preview build.