I’ve always been confused about how I should align the rotation axes of my controllers in relation to the rotation axes of the joints.
For example, I was watching Aaron Holly’s rigging DVD and in his spine rig he has the rotation axis of the joints with Z facing back and the rotation axis of the controllers with Z facing forward. I attached a picture to show what I mean.
I was wondering why didn’t he align the controllers’ rotation axes to be the same as the joints? Does it not really matter if they’re different from each other? Thanks.
It really depends on how your connecting your controls to your joints. If your just constraining them together a lot of times it doesn’t really matter. It really depends on the circumstance and the animators your working with. Our skeleton for run time may run down the bone one axis but the animators will want a different axis for twist on the controls. there is no rule though about having your controls and joints match rotation axis.
There’s some magic kung fu regarding the order of operations to avoid gimbal lock. I think it’s that X gets calculated first, then Y, then Z, so by making X the twist you can minimize gimbals.
But that was a long time ago, and it’s probably wrong by now. =)
[QUOTE=lkruel;11328]There’s some magic kung fu regarding the order of operations to avoid gimbal lock. I think it’s that X gets calculated first, then Y, then Z, so by making X the twist you can minimize gimbals.
But that was a long time ago, and it’s probably wrong by now. =)[/QUOTE]
Just select the rotation order that works best.
Usually it is not important to worry about the control and joints alignment, however sometimes its necessary so its good to know how it works. We do not orient joints and do not match axes of joints to controls.
When dealing especially non-uniform scale then it is an important that they match or you get some really crazy problems.
The other time when you are using direct connections instead of constraints it is also easier to have the rotate orders and orients matching otherwise you end up with some unexpected results. Even orient constraints can have issues if the values are to far off from each other.
also if building a procedural autorigger, you can build the joints first, then orient the controls from them or vice versa. Anyway, consistency is generally good.
