Now free to play.
Tilt Brush lets you paint in 3D space with virtual reality. Unleash your creativity with three-dimensional brush strokes, stars, light, and even fire. Your room is your canvas. Your palette is your imagination. The possibilities are endless.
Review by lapBAR:
This was abandoned by Google, but they made the code open source. Open Brush is actively being developed and is completely free.
See also OpenBrush, which is a community-built continuation of the TiltBrush source code for both PC and standalone VR. https://openbrush.app/