Anyone know of a tool for visualizing an objects momentum or intertia?

Does anyone know of a tool that would calculate the momentum and angular momentum of the armature center of mass and display it for the past X number of frames?

As I try to animate I am noticing how hard it is to preserve an objects inertia/momentum correctly. For example if I try to animate a character running across a roof, and diverolling into a two story summersault. It is very difficult to keyframe the fall so it is believable. My character’s rotation looks like it is affected by phantom forces and his acceleration and deceleration also look distorted from a naturally falling object.

I could try to use physics but I want to keyframe it. I have looked at ghosts and motion paths but I don’t think they do quite what I am looking for.

What I want is something that would calculate the momentum and angular momentum of the armature center of mass from frame to frame and display it for the past X number of frames. Then, I could add a falling physics object and make sure that the center of mass of my armature follows the falling physics object. Same for angular momentum. Also if my armature center of mass ever changes direction I could check to make sure there is something that generated the force needed to produce this change.

Thanks.

So your animating a Character to do Rolls and Somersaults?
am I understanding you correctly?

are you having any kind of issues with your modeling going into Gymbal lock?
that can cause oddball issues when your trying to do 360 degree (or even 180 degree) rotations…

Animation in general is a Learned and practiced thing… more of it you do the more you figure out how to make something look the way it should…

Observation I think is the key in animating…

you may have to capture some video of people doing tumbling and even place these in the back ground of your Blender animation such that you can match your character to movement of the video frame…

Welcome to BA!!

Sorry, but no, there’s no tool like you’re looking for. Physics sims won’t help you either, with them you have no control. I just tried using blender’s rigid bodies sim to help with animating a cell phone falling from a table. It worked, it just didn’t work right. I needed one specific corner of the phone to hit the floor, couldn’t get the sim to do it. It always landed on the floor in a way I didn’t want it to.

Like norvman says, animation is a learned and practiced skill, and observation is also important. Once I thought I knew blender well enough to start animating, I thought I was ready to take over the world. I just started animating characters, how hard can it be? Just move the character and keyframe it, done. Who needs to do bouncing ball exercises??

Turns out I needed them, because I’m doing them now, and I think you can learn all you need by doing them as well. Here’s a link to some animation exercises I cam across: http://www.animatorisland.com/51-great-animation-exercises-to-master/

Everything you are trying to do is covered in the first level exercises on that list. Learning how objects move, how a ball bounces, how a brick falls is what you need to know. A person running across a roof will move with great speed until they leave the roof, then forward momentum will slow to a stop, as gravity kicks in, they sill start to slowly fall, and pick up speed as falling with a sudden stop when they hit the ground. Pretty much like a ball would if you rolled it across a flat roof and it fell to the ground…

Best of Luck,
Randy

Looks like that first level list is a bit abbreviated. Maybe the author was eager to begin working with characters. Here’s some suggested additions:

a) chain swinging from a peg
b) billiard ball striking another billiard ball
c) billiards with bounces off billiard table rail
d) dropping a ping pong ball; tennis ball; baseball; bowling ball (increasing density and weight) onto a hardwood floor
e) same as (d) only the floor is a rubber mat

Another challenge is to animate some of those exercises that obviously require a character with some simpler object, like a ball or a pickle.
eg: scared pickle peering around a corner, or, billiard ball changes from happy to sad.

These distill animation down to its essence. If you can make a pickle look scared, you can make anything look scared. :wink:

PS: @DigitalOpus: you might want to try your scene with a billiard ball, to get the overall motion looking right, then use the ball center locations and rotations for your character. It’s easier to work with a ball than a full blown character, and you can see whether the physics looks right more easily, because there’s really nothing else there.

Welcome to BlenderArtists :smiley:

@ revolt_randy and Orinoco

Wow… guys thanks for the list…
I been messing with 3D animation for years and still havent’ even gotten close to doing all of these…
I better get to work!

LOL!

Wow! thanks for all the great responses and for the great list of resources.

I had a look at this list and am working on the exercises. I also have been reading up on Disney’s Illusion of Life 12 Principles.

I am a total beginner at animating so I may be completely talking out of my ass about this, but the more I try this, the more I think this is hard because the tools make visualizing an objects weight (center of mass) and angular momentum hard to see. I can only see one frame at a time. To see how the center of mass is moving I need to play the animation, change camera angle, play again adjust, play again etc… The feedback is indirect so the process is slow and involves a lot of trial an error and experience. I need to guesstimate where the center of masses are.

I am thinking of writing an add on that will work like ghosts, except instead of displaying bone positions it will display the center of mass path and angular velocity for a system of bodies. Then it would be much easier to see what is happening to the weight of my objects in the scene over time.