"Smart" making of Circular Arc of Motion for 3D Animation Keyframing WITHOUT requirement of extra FK-behavior higher hierarchy Bone/Rig structure: Allow Blender to READ and PROCESS the 3D Animator's intention through the use of 3D Cursor Transform Pivot Point on a Posing Bone for F-Curve Interpolation Keyframing

Hello, fellows!

This proposition wants to make Rigging & Animation in Blender a more sane "duo".

If you are familiar enough with conventional princinples of Rigging & Animation at least inside Blender, then you probably know this critical limitation in the current system: a single Bone, being Posed directly on its own (which I call a 'Loose Bone'), is incapable of 'recording' an Circular Arc of Motion in 3D Space (part of the F-Curve Interpolation Keyframing process), even though [and here it is how shocking it becomes!] we can actually see, during the Posing process, a hypothetical Circular Arc of Motion, for example, using the simple 3D Cursor Transform Pivot Point on any choosen Pivoting Point in the Scene.

One current problem or limitation is that Blender' system of F-Curve Interpolation Keyframing has a structural 'blind spot' to that kind of Posing Option functionality; that system is currently uncapable of 'reading' (during 3D Posing) and then 'processing' (during the process of constructing its Automatic F-Curve Interpolation) the 3D Animator's real intention. It will only understand that intention, either: 1) with a rigid Rig structure which implies that the 'Loose Bone', is dependent of another higher hierarchy Bone (often, just a Parent Bone, but also certain Bone Constraints can mimic that without any Parenting Relation) just in order to be capable of spontaneously Generating a perfect/ideal Circular Arc of Motion [with the ADDITIONAL drawback that we then need to Pose the FK-behavior Bone and not the 'Loose Bone' in order to achieve that result; so, 2 Bones to complicate the process instead of just having 1 really 'indepedent' Bone], 2) by Adding a Keyframe breakdown in the middle of an already generated, linear [and undesirable in this case] Interpolation between 2 Keyframes [but not only this adds a lot of more steps to everything if we use this too much, but this also doesn't help totally in getting the more ideal/'perfect' Circular Arcs of Motion that we can get spontaneously through the FK-behavior Bone, a conventional --but extremely rigid and problematic-- Rig structure.

Maybe you are aware already of the following; but some genius person made a Paid Addon that has some relationship with this proposal. It is the notion that we can make Blender's internal F-Curve Interpolation Keyframing structure really 'understands', or 'interprete', the vision of the 3D Animator youtube.com/watch But of course I'm not suggesting anything like that, which is much more keen with 2D Animation for 3D Animation; what I'm proposing here, is to find a way to solve a 3D Rigging & 3D Animation problem/limitation of Blender, which, if solved, could help, on one hand, Riggers to get simpler and effective Rigging experience in Blender [making 'Loose Bones' structurally more 'independent'] , and, on another hand, helping 3D Animators in Blender having a much better time, tackling more with Posing Options than with extra Bones, extra Bone Collections, extra Channels and extra Keyframing, which just mean we're dealing with older tech which needs to be revamped and empowered with better solutions.

Finally, bwloe some images just to illustrate.

Here, we've got an extra FK-behavior Bone that is needed in order to Control the spontaneoulsy 'Perfect' Circular Arc of Motion made by the IK Hand Controller Bone.

But here.in the next 2 images, we are trying to use the 3D Cursor Transform Pivot Point [btw, an "Empheral Rigging" Posing Option, although unfortunately here partially limited by design in Blender currently regarding its Keyframing aspect] in order to attempt that same spontaneously 'Perfect' Circular Arc of Motion... but it fails!

Naturally, Blender's F-Curve Interpolation system, currently, is incapable to 'understand' what the 3D Animator wants. I believe it can be made cacapable. For that, I can rationalize that it would, at least, to take into account , during the process of Posing a 3D Character for 3D Animation, the Posing method that is being employed on Pose Mode . So, we could have this spontaneously 'Perfect' Circular Arc of Motion generated (in bluish color), instead of a Linear Motion (in reddish color and streaked out), for even a 'Loose Bone':

Maybe, developing that feature, would be just enough, in order to make any 'Loose Bone' more indepedent of its(their) respective 'FK-behavior Bone(s).

Thanks for the attention!