Microsoft Maquette, currently still in beta, is a program that allows users to prototype scenes in VR using pre-made assets; similar to Google Sketch up, but with a wider reach than architecture. Originally designed for Microsoft’s own developers, its powerful tools make it easy to storyboard 3D environments. Currently available for free for Windows MR, the Valve Index, HTC Vive, and Oculus Rift.
Microsoft Maquette - create 3D content in VR