Explain how to unmap avar for smooth animation

[davelab6]

As @lorp points out in https://twitter.com/axis_praxis/status/1285979080018493443?s=19 there is a downside to avar space warping, which is that the shadow variation engine used to coordinate parametric axes can help with, unwarping the space for smoother animation.

[Lorp]

There’s also a discontinuity affecting animation smoothness at the Default (“the avar mapping you get for free”), unless delta magnitudes in min and max have the same proportion to axis distance from default and delta directions in min and max are exactly opposite.