Hi cj,

It is completely legal to let joints have positive and negative rotation values. For example, I usually set up a spine such that positive rotate x curls the spine forwards (so that the character's head is now looking towards their navel), and negative rotate x curls the spine backwards, (so that the character's head is now looking to the sky)

The reason why I do this is that when an animator is looking at the fcurves in the curve editor, they can easily see when the joint is at default (0), bent forward (>0), or bent backwards (<0). Having 0 as the default position also allows an animator to reset the character to default simply by zeroing out all values.

Take a look at this document for more information. It also covers another important topic: rotation orders. https://www.riggingdojo.com/2014/10/0...-orient-wrong/

You can also take a look at this tutorial for a more concrete example: https://www.3dtotal.com/tutorial/82-h...ean-hewitt-lra