Today when you buy a 3D printer, it comes with its own custom set of software to install to control it, which might or might not be the same tools that work with any other 3D printer you use.
If you have access to a 3D printer at school or in a shared facility, you'll probably have to export your designs in and out of different packages (and hope they all interpret the design the same way).
Microsoft is adding native support for 3D printing into Windows 8.1 to make it easier for you to print from different applications on different 3D printers without having to export and import design files. With a supported 3D printer, you can just select the Devices charm and choose Print (or use File, Print in a desktop application) and see a 3D printer connected to your PC the way you would with a normal printer.
New 3D printing APIs
We tried it out with a MakerBot – a popular 3D printer that Microsoft will be selling in Microsoft Stores; you get the logical choices like what material to print with and whether the object is solid or hollow in a familiar interface that looks like picking paper size and whether to print in colour.
For an app to work with the 3D printing support in Windows 8.1, it has to support the new 3D printing APIs in the platform; Microsoft is releasing a SDK at Build so developers can do that more easily and several other printers (including some open source 3D printing projects) already support it. It's not quite universal 3D printing, but it's a great start on simplifying a technology that's going from hackers and hobbyists to mainstream.