This shows an implementation of a Spherical Radial Basis Function node. SRBF is commonly used in lighting calculations like this http://www.cse.cuhk.edu.hk/~ttwong/papers/srbf/srbf.html. I am using SRBF here to track joint position and orientation. This gives me a weight value per target that I can then use to drive corrective shapes. Each target point has its own falloff and twist attributes to adjust the triggering sensitivity. The rig is my free quadruped rig, Nico, which you can download here:https://www.creativecrash.com/maya/downloads/character-rigs/c/nico. The download does not include the SRBF node since it requires a plug-in.