Anonymous at Wed, 1 Sep 2021 07:34:34 UTC No. 847939

Taking a course in classical mechanics will provide the foundation necessary to understand what you're asking here anon.

If you understand basic rigidbody physics you're familiar with how all translationss of a body revolves around it's common center of mass.
Any energy impulses put into the body will act against the inertia and angular momentum of the entire system around this one singular point.
It demystifies why what and how something has to move in order to produce naturalistic motion as you translate from animation pose to animation pose.

When you animate you will look for the center of mass to follow smooth flowing trajectoris thruout the inbetween animation and not jittering
about altering it's direction and position eratically from one frame to the next.

Tracking and understanding the center of mass is the key to capture all that subtle counterbalancing that automatically occurs in nature.
It aids you in creating motion that looks natural and doesn't blatantly violate any physics by introducing fake looking forces into the motion.

Anonymous at Wed, 1 Sep 2021 07:37:28 UTC No. 847940

>>847939
never seen a classical mechanic class for animation
>basic rigid body
you cant effect bones with it cant you?
otherwise you d be createing simple ragdoll but not walks.
>tracking to get balance
how do you do this?
seems overkill just trying to catch characters steps from a frame to another.
are you sure of this?

Anonymous at Wed, 1 Sep 2021 08:33:10 UTC No. 847952

>>847940
>never seen a classical mechanic class for animation

Me neither, I meant a standard classical mechanics course. That was a real eye opener for me when I took it as an adult getting into game physics.
I was already an okay animator but I did it all thru instinct. Understanding the underlying phenomena on a more complete level filled in a lot of blanks.

>basic rigid body you cant effect bones with it cant you?

Yes you can, you don't have to worry about the fact that you have lots of interconnected bones and limbs
You'll just treat your whole character in whatever configuration it is in in the given frame as a single rigidbody.
The physics works out close enough for you yo mimic what's actually occurring in nature this way.

>tracking to get balance how do you do this?

The center of mass is the average position of the mass of each of your body parts. This can easily be solved for with a script or a position constraint.

>seems overkill just trying to catch characters steps from a frame to another.

It's easy to do and it eliminates a ton of guess work on your part as an animator.
The none-analytical approach of winging it on pure instinct is a lot harder to pull off, will eat more of your time and deliver worse end results.

>are you sure of this?

Hell yeah, you take something that is really finicky and impossible to do by hand and turn it into something that is comparatively easy to pull off.
Bar to entry is that you need to pay the prize of investing time and effort into actually understanding what you are doing on a more fundamental level.

Anonymous at Wed, 1 Sep 2021 08:39:38 UTC No. 847954

>>847940
Forget about classical mechanics and rigidbody physics. Get a copy of 'The Animator's Survival Kit' by Richard Williams, study references (Eadweard Muybridge's work, for example), maybe take a course on animation...

Anonymous at Wed, 1 Sep 2021 08:50:00 UTC No. 847955

>>847952
ok effort post but i really need to solve one thing at a time so pls keep it short...
so
>classical mechanics for animation
>basic rigid body
>tracking
>sure, hellyeah
ok in summary, i dont see WHICH
>brainlet i know
classical mechanics work to ballance legs and arms, since they have like... 3DOF, and classical mechanism seems to work on 2, so its two dimensional

even with rigidbody i honestly dont see which force motivates the leg to balance itself so, enlighten me? basically i need informstions of forces that motorizes balance and natural motions, of sorts.
>position constraint
no, the constraint just hold it in place isnt it?

>>847954
sorry for spoilers but richard williams isnt exactly three dimensional despite havin 3d motion of sorts

so to sum all these, which motions helps balancing the left and right part of the body?

Anonymous at Wed, 1 Sep 2021 08:51:30 UTC No. 847956

>>847955
Consider this depiction of a 'Dive Kong' parkour move.

My automatically calculated Center Of Mass (COM) is the red ball as indicated in the picture and red line it's trajectory.

As my character goes from a upright into the 'dive' position she curls up like a cat in passing with the arms placed on the wall
and then unrolls herself to prepare for the landing on the far side.

During this simple sequence of motions her COM passes all over the place, inside and outside of her body, even my best guesstimations
as an artist of exactly where this position is would be flawed and as a result her airbourne trajectory would look floaty and weightless.
I would have to tinker back and forth and make a lot of careful observations trying to tweak it out.

Now thanks to me seeing the COM's position I can just alter her overall location in space from pose to pose until the COM follows
a smooth flowing pathway that are not much harder to get right than animating a basic 'Bouncing Ball'.

As a result this massless skeleton can now easily be made to follow a near identical trajectory a live athlete performing the same movements would follow.

Anonymous at Wed, 1 Sep 2021 09:04:58 UTC No. 847958

>>847956
uh yeah thats good.
okay we use the COM as the sort of motion for the character's center, so then all objects follow these COM's somehow.

As an artist of course you guesstimate these positions. So then naturally what does the parts do, to so called produce the "balance" or naturality of its motions? since both legs dont move together but always late by a time... ? using COM as an inference?