Bouncing Ball

[robcat2075]

It has an inconsistent forward speed and something is also wrong with the vertical spacing.

But without being able to scrub the animation file one frame at a time it is difficult to diagnose.

It's MUCH better to post a quicktime file for crits because those can be scrubbed frame by frame and Youtube can not. Neither can Vimeo.

[icra]

It has an inconsistent forward speed and something is also wrong with the vertical spacing.

But without being able to scrub the animation file one frame at a time it is difficult to diagnose.

It's MUCH better to post a quicktime file for crits because those can be scrubbed frame by frame and Youtube can not. Neither can Vimeo.

Thank you for the replay.
Here is your .mov file. (http://www.2shared.com/file/8537040/f6d1679e/bounce.html)

Regards.

[giordi]

i think that the first bouncing is a little to long and at the end the ball increase the speed and stretch the bouncing

[robcat2075]

The second version is much better.

But notice that on the first bounce it rebounds faster than it landed.

The first arc is a bit flattish at the top, the others may be a bit flattish on the sides.

Also on all the arcs the apex is closer to the left than the right so the ball's forward motion is faster on the second half of the arc than on the first.

[icra]

The second version is much better.

But notice that on the first bounce it rebounds faster than it landed.

The first arc is a bit flattish at the top, the others may be a bit flattish on the sides.

Also on all the arcs the apex is closer to the left than the right so the ball's forward motion is faster on the second half of the arc than on the first.

Thank you for the e-critique, i will correct the mistakes.

[icra]

Hello,

This is a new animation for a bouncing-ball with rotation.

Here is the mov file of the video. (http://www.2shared.com/file/9042718/f376bb49/bila_cu_rotatiebun.html)

And here is the video on youtube:
http://www.youtube.com/watch?v=EmClT48AJ5A.

Please e-critique.

Best regards.

[icra]

Hello,

This is a new animation for a bouncing-ball with rotation.

Here is the mov file of the video. (http://www.2shared.com/file/9042718/f376bb49/bila_cu_rotatiebun.html)

And here is the video on youtube:
http://www.youtube.com/watch?v=EmClT48AJ5A.

Please e-critique.

Best regards.

Please critique.

http://www.vimeo.com/7537316

[thehive]

gettin there still sliding can u post your curves so we can see whats goin on

[giordi]

yea there is sliding post the curves will be easier for us help u ... i think personally that the spinnging of the ball is not fast enough

[icra]

yea there is sliding post the curves will be easier for us help u ... i think personally that the spinnging of the ball is not fast enough

It is ok if i make a print screen for the curves?

[giordi]

yeah we meant that

[icra]

yeah we meant that

Ok here it is! Many thanks for the critiques!

http://i35.tinypic.com/jb4pyx.jpg

[PowderMonkey]

i think your second attempt is much better than the first.

i think it looks good until the ball starts to slow down as it rolls across the floor. it keeps spinning at the same rate, although it isn't moving at the same rate, so it looks like it slides across the floor. this isn't a bad thing, necessarily, because you may want to control that (like if you were creating a bowling ball - they sliiiide before they start rolling). just be aware of it, so if it isn't what you want, you can correct it.

the other thing that catches my eye is that the first few bounces cover the same amount of floor space, even though the earlier bounces are higher. what i mean by this is that if your ball is traveling at a constant speed, it's going to go further on a higher bounce than it is on a lower one. your curves should look like booouuunce boouunce bounce bnce bce b... roll

i've linked to an example i've made, and the curves are below.
some things to note:

-as the ball leaves a bounce, it's going to accelerate or decelerate, depending on how it's spinning. this acceleration is going to also apply to the spin - it will spin faster or slower after each bounce depending on what's happening.
-no squash or stretch on your ball means that it's a really hard ball, and that it's going to keep bouncing for a while. lots of squash and stretch will mean that each bounce will absorb some momentum, and it will bounce only a few times. if you choose to animate squash and stretch, be aware that the ball is going to squash into the floor for a few frames before it leaves the floor. this is a mistake i see a lot of people make.
-the other mistake i see a lot on realistic animation is that squash and stretch are reactions ; the ball isn't going to stretch before it's hit the ground and squashed up first.


if you look at the translate curves, you can see that i've got 3 contact frames, to allow for the squash into the ground, and the recoil as it leaves the ground. see that the translate x curve gets steeper on each recoil frame - the ball speeds up as it leaves the ground.

look at how the translate y - the bounces - are really wide to start with, and get shorter and shorter as they get lower and lower.

if the scale curves confuse you, just know this - the big rule of squash and stretch is that an object should keep a constant volume - as you stretch it, it'll get thinner, and as you squash it, it'll get fatter. so, if you squash along y, you need to apply the same motion in reverse to x and z.

take a look at the scale curves, but just look at the keyframes, don't worry about what the curves are doing. notice how i have the same 3 keyframes for each contact as in the translate y curves. then, a few frames later, there's another one, and then another on again after that. this is because the ball squashes as it hits the ground (1 and 2), restores to its original shape as it leaves the ground (3) , stretches in reaction to the squash (4) and gradually returns to its original shape in flight (5).

finally, see how the rotate z curve gets steeper as time goes by? as the ball leaves contact with the ground, the spin increases each time. this will only start to slow down after the ball has finished bouncing and is rolling. if the spin was in the opposite direction to the movement of the ball, then the spin would decrease on each bounce.


hope this helped =)


the movie has two balls, with exactly the same animation. one is slower paced, so you can see more of what is going on.

bouncing ball (http://airstre.am/ballbounce.mov)

http://airstre.am/ballbounce.jpg

[giordi]

personally i think that 3 second of sto on translate should be a little bit too much but it's look work , ok now you have a lot of think and work i'm waiting for new update of ur work

[icra]

Thank you PowderMonkey and giordi for your coments and critiques, i will analize and i will come with updates.

[icra]

Ok, this is my new ball bounce with squash and stretch.

http://vimeo.com/7649947

Please give me your opinion or your e-critique.

Thank you very much for your's future posts.

[giordi]

oh that looks good!
i feel the spinning a bit slow for the speed that the ball has...however... never stop an animation in this way because it's like u are watching a really cool movie and somebody hit u in the abs! XD

[PowderMonkey]

nice work!

the principles of animation are really important, and a bouncing ball exercise is a good way to cover a lot of them in one go.

remember that it's ok to break the principles, as long as you know why you're doing it and what effect breaking them is going to have. (personally, about the only time i veer away from them is when i'm exaggerating something)

explore for yourself, and most importantly, have fun!

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