Advanced character rig (4/???)

Whelp, it kinda looks like the body portion of my custom character rig is now complete.

This took an inordinate amount of time and effort to construct (especially inside C4D). To be honest, I'm not even sure if this would be possible with a copy of C4D straight out of the box, since it took an awful lot of custom code to get this far. However, pretty much everything about the body works perfectly and I'm reasonably happy with the results.

Rig features:

- Fully hybrid IK/FK system

Each major component of the rig (legs, spine, arms, and hands) can be transitioned between IK (inverse kinematics) or FK (forward kinematics). This is useful for handling situations where either system is insufficient for representing the required pose given a particular situation. Furthermore, IK/FK blending is virtually required for proper animation- while I still don't know if I'll be able to render out something like that in the future, the rig is certainly capable of handling anything I can throw at it.

- Full IK/FK pose translation

This kinda goes hand in hand with the previous feature, since you don't want to rebuilding the pose on the IK or FK side of things just so that you can seamlessly switch between the two. As such, the rig can automatically translate between the IK and FK systems with the click of a button- automatically matching the joint rotations from one to the other (and yes, this even works when going from FK to IK- and no, that wasn't easy to implement).

- Completely stable joint rotations

All joint rotations are completely stable from -180° to 180°. This is extremely important for this particular rig because the base character mesh has well over 177 joint corrective morphs assigned to it, all of which are slaved to the individual rotations of the joints. As a result, every single joint needs to be flip free (ie, -31° can't suddenly flip to 149°) and remain totally stable for any pose the rig is capable of representing.

- Fetish friendly viewport controls

I can' really make that big of a deal about this one, but a lot of the controls were specifically designed and tweaked over time to accommodate expandable character meshes. This means that wherever possible, controls need to stay out of the way of the character mesh when inflated- or if they can't, they need to remain as accessible as possible so they can still be selected and manipulated from the viewport.

- Custom 3-joint finger IK solvers

As with the rest of the rig, everything that can benefit from IK is IK enabled, including the fingers. This is a completely new and proprietary way of handling finger posing that I'm pretty sure is totally original as well. In IK mode, each finger only has two controls- a metacarpal target locator, which can be used for things like cupping or splaying- and a finger tip locator that determines where the tip of the finger should land up. Auxiliary to that are two finger modifiers- pressure and tension. Pressure simulates force downwards onto the finger, causing the the last joint to bend inwards towards the palm as if the character were pushing into a hard surface. Tension simulates the opposite- as if the finger were looped around something and being pulled away from the hand. This system allows for quick and easy finger posing in relation to exterior hard (or soft) surfaces. As with everything else, if the IK system can't fully represent the required pose, it can still be used to get most of the way there and converted into an FK pose where further adjustments can be made.