Unity is a game engine that can be used to create AR or VR environments. It allows for importing different art assets, playing animations, creating materials (textures and mapping), and creation of scripts which "allow you to trigger game events, modify Component properties over time and respond to user input in any way you like."
VRTK is a tool kit that was made to help in building VR environments. It can help handle moving in the virtual space, interacting with objects, and more.
