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#101 Rodney

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Posted 31 January 2012 - 04:55 AM

Here's another random thought to consider (its definitely something I hadn't considered) Muscles do not stretch. They contract and they relax. This is an important distinction (I think). As bouncing balls generally do not have muscles we are fairly safe in the knowledge of this.
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#102 robcat2075

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Posted 31 January 2012 - 10:40 AM

I'm not trying to irritate anyone with my explanation of gravity and squetch on bouncing balls, but if I'm giving comments on gravity and squetch I'll likely do it in the framework that made it all make sense for me and gave me the most information to carry forward to other animation that is not bouncing balls. That's my story and I'm sticking to it.

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#103 itsjustme

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Posted 18 February 2012 - 03:30 AM

Here's the updated 04 ball bounce...I think it's working, but I've been wrong before. All notes, models, Choreographies, renders, etc are included in the ZIP.

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#104 Rodney

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Posted 18 February 2012 - 04:09 AM

Glad to see you are still plugging away at this David. Just a few hours ago I saw a bouncing ball exercise and it made me think of you. ;) Downloading your latest but don't know when I'll be able to get a chance to look at them.
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#105 itsjustme

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Posted 18 February 2012 - 01:32 PM

Glad to see you are still plugging away at this David.


I've been trying to get back to this for a few weeks, but I haven't had much free time. I've got a lot of things to catch up on.

#106 robcat2075

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Posted 18 February 2012 - 04:47 PM

Hi David,

My main crit would be that I prefer much less stretch prior to impact. There is a tendency for the top of the ball to look like it has caught on something when the ball is moving so slowly. (Some animators teach to leave descending stretch out entirely.)

Stretch as "motion blur" was probably more important when they were animating on twos and if the ball was moving much faster.

During the time on the ground I've found i like to do the squetch asymmetrically... most of the time is spent squashing down and just a frame or two is spent stretching back up so that the upward leaping motion is as fast as possible in the available distance. I want to get the ball's mass moving upward as fast as possible so a gradual stretch up won't do.

Here's a small experiment I did to see how long i could keep the ball on the ground. This is verging on too long, the ball is starting to look stuck to the ground. But if you frame through the first bounce you can see the asymmetrical timing in action. Lots of time spent squashing down as the ball has slammed into the ground, then a fast leap up.

Attached File  SquetchyBounc000.mov   759.93KB   21 downloads

However, I think you have the fundamentals of Bouncing Ball going well and should graduate on to the next exercise which would be a ball bouncing in an obstacle course. This involves proper handling horizontal motion and bounces off of angled surfaces.

Robert Holmén
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#107 itsjustme

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Posted 18 February 2012 - 09:57 PM

More food for thought. Thanks, Robert! I'll make the next one the obstacle course.

#108 TheSpleen

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Posted 19 February 2012 - 11:04 AM

I am excited about this! I have a project going but THIS I wanna do.
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#109 robcat2075

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Posted 19 February 2012 - 11:17 AM

I am excited about this!
I have a project going but THIS I wanna do.


I think there will be a bouncing ball chapter in New TAoA:M... if I ever get around to it.

Robert Holmén
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I solved your problem? buy me something (used is OK!) Big thanks to... NancyGormezano, Roger, cribbidaj, thefreshestever, Tom, Dalemation, Simon Edmondson, thejobe, Rob_T (2 more x), agep (again!), itsjustme, jason1025(+1), dblhelix (+1),markw, Roger (3x!), mouseman (x 2!), Xtaz, agep, Gerry, thefreshestever, dblhelix (twice!), jason1025, Luuk Steitner, PDM, Rob_T and Dhar!


#110 Rodney

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Posted 07 May 2013 - 02:03 PM

I just read through this topic again and enjoyed it immensely.
Thanks for linking to it again David! :)

For those that like to read ahead... check this out:

EHBsn1fzUog

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This video covers a lot of territory but also discusses some common errors in animating arcs.

Note: This and many other resources have been made available by Alejandro Garcia who is something of the defacto Physics Professor of the Bouncing Ball and various other animation physics. (REF: http://animationphysics.org/)
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