In order to make realistic VR content, it's not enough to simply program some 3D objects. To truly mimic real physics, you have to be able to track objects, and in some cases, even use object tracking to capture realistic movements that wouldn't translate too well if an animator attempted to hand-rig them to a 3D model. VR tracking is, of course, also at the heart of full-room VR, letting a VR rig keep track of players and objects in a program within the room. The brand of VR tracking used by Valve, present in the HTC Vive, is called SteamVR, and it's now available for licensing and use royalty free by any interested developers.
SteamVR's tracking algorithms are a bit on the complex side, but to put things as simply as possible, a base station tracks sensors down to fractions of a millimeter at a frequency of about 1,000 check-ins per second to produce extremely realistic and fluid movement. The system was painstakingly developed by Valve, with help from HTC, and is one of the most advanced VR tracking systems on the market right now. The system is scalable, resistant to outside influences, and extremely accurate, with sensors that can be used in the system available for fairly low prices. Licensees can get their hands on a comprehensive development kit that includes all of the hardware you need to get started, including sensors, circuits, base stations, and additional peripherals.
With VR being a young space, developer advocacy is the name of the game right now, and Valve has that angle covered. In partnership with online learning site Synapse, Valve has created a comprehensive curriculum that should take anybody who's fairly familiar with the HTC Vive to the level of being able to competently develop for it. The classes are set to begin in September, and the tuition cost is $3,000. The classes cover all of the electrical and mechanical considerations for development, as well as design, simulation tools, integration, troubleshooting, and a number of other topics that developers may run into while creating software for the HTC Vive or any other virtual reality system using SteamVR.