James Snowden writes:
RBF drivers are a fast, simple way to significantly enhance rigging in Blender. If you're trying to solve issues with constraints, fiddly weight-painting, or complex and time-consuming driver setups, RBF drivers can often provide a solution in minutes that would otherwise either take hours, days, or not be possible at all.
Having seen the benefits of RBF (radial-basis function) systems in other software such as Maya and Unreal Engine, I wanted to bring them to Blender, but in a way that worked for Blender users: seasoned professionals and relative beginners alike.
RBF drivers offer something very unique over constraints and other driver types. Instead of defining how you want the rig to do something, you define what you want it to do. Simply move your character's bones, adjust controllers, shape-keys or other properties until things are exactly how you want them to look, and record a "snapshot". RBF drivers will fill in all the blanks for you and smoothly interpolate everything while you pose or animate.
