Pixar’s USD format allows representation of dynamic 3D scenes. It lets designers create large numbers of objects that fit together into a scene. People on a team can work independently of each other, each designing certain parts. The project is on GitHub.
USD’s design solves the problem of not having to work with one monolithic file (as Pixar did for Toy Story), but sometimes a monolithic file is useful. At WWDC 2018, Apple and Pixar announced a new wrapper for USD, called USDZ. It’s a Zip archive with some special rules. iOS 12 will support it.