itsjustme

There's the problem. A ball that falls from half as high does not take half as long to reach the ground. It takes a bit longer. A ball falling from 6 feet takes longer to fall thru the first 3 feet than the second 3 feet, right? Because it was accelerating all the way thru. Consider a ball that falls from 6 feet, bounces up and falls again from 3 feet. The new fall from 3 feet should take as long as the first fall from 6 to 3 feet. Consider that a fall always starts falling from a velocity of zero, no matter how high or not high it has bounced. Hmmm, I'll have to digest that a little. I assumed that on the second bounce (and after) it would also fall 1/4 the distance at 1/2 the height and would have the same curve to the spline as the first bounce. ------------------- EDIT ------------------- I'll let it sink in for a little while and tackle it when I get home.

When I get home this evening I'll see if I can figure out where I went wrong...I'm stumped at the moment (I can't take a look at it where I am).

This is a trick question. If I'm understanding the question, it would be the same rate. That rate is on the chart from animationphysics.com that I linked to in the notes. Yes, it will always take the same time to fall x feet, no matter what height it starts at. Now... how can we use that to inform how long each bounce takes? I made each bounce last half as long because I thought I made each bounce half as high...unless I made a mistake in there somewhere.

This is a trick question. If I'm understanding the question, it would be the same rate. That rate is on the chart from animationphysics.com that I linked to in the notes. Where I possibly went wrong (I think) is that I assumed that using the exact same bias settings on each bounce would produce the same results if everything was scaled equally...that might not be the case. I didn't check it close enough is what I'm thinking.

I'm not sure what you mean, Robert. I used the tutorial (from http://www.animationphysics.com/) that is linked in the notes to figure how fast the ball would fall...did I misunderstand the tutorial or is there something wrong with the tutorial? I used the same rate of fall for each bounce because there was no force other than gravity involved...was that inaccurate? ------------------- EDIT ------------------- Or maybe I just thought I had made it the same rate of fall....I'll have to check later today. I assumed a couple of things, I'm thinking. ------------------- EDIT ------------------- According to the tutorial, it should have been 1/4 of the distance at 1/2 the time...so, if the height was 48 inches (the initial height I used), it would be approximately 36 inches at 6 frames since the ball should take 1/2 second to hit the ground (also according to the tutorial). I adjusted this slightly, so mine was around 37 inches at 6 frames...I explained it in the notes.

Extremely cute, John!

An entire band! Should be interesting, Gene.

Okay, let's see if I can do better than the first attempt. I made a modification to the squetch ball to make adjusting the direction of the squetch easier (for me at least)...I think it helped. If it survives a bunch of testing, I'll be adding it to the Squetch Rig. To "call the shot" I made a quick set of notes that include captures of the timeline and the animations in the "bouncing_ball_exercises_01v2_notes.zip". The squetch ball, Choreographies and another copy of the renders is in the "bouncing_ball_exercises_01v2.zip". I've got the second exercise partially completed, but I think I'd better wait for the critique of this one before I go farther with it. Constructive critiques are encouraged. Thanks in advance for any pointers. -------------------------- EDIT -------------------------- I realized after posting this that I should have cleaned up curves on the 'X' movement of the Null target. It isn't extremely obvious and I don't have time to correct it at the moment, so I'll leave it as-is unless I need to make another version. bouncing_ball_exercises_01v2_notes.zip bouncing_ball_exercises_01v2.zip

That is fantastic, Serg!

Happy Birthday, Charles (DrPhibes)!

Happy Birthday, Rasik!

Happy Birthday, Sebastian (thefreshestever)!

Those differences will be in subsequent exercises, Rodney. However, the first exercise has already demonstrated that I need to get a handle on the most basic stuff...general physics as it would appear in the Timeline window F-curves. The next exercise will use a soccer ball, but part of it will use a more extreme squetch than what would be typical so that I can get a better handle on the F-curves of squetching an object...it won't be a real-world soccer ball in every part of the exercise. I'll call my shots on the subsequent exercises so that it is clear what I'm trying to accomplish.

No problem. I'll probably be en vacances by then, so I may not get to looking at it until next week. Probably for the best, I'm thinking I should spend a few days on this anyway. Hopefully, it will mean a better finished exercise...we'll see. Have a great Thanksgiving, Robert!

Is there a way to zoom while maintaining a 1:1 aspect ratio in the Timeline? I can get close using the grid as a guide, but I'm thinking there is probably an easier and more accurate way. I ran out of time this evening, so I'll have to post the update for this tomorrow night. Sorry for the delay.

I would agree. For arms, legs, fingers, etc I tend to use eight CP rings.

Very helpful, Robert! Thanks for taking the time to critique this. Animating is a weak spot for me and this illustrates how much work I need to do. I'll re-tweak these and update the post tonight.

I'll do some more tweaking. Thanks, Mark!

Your opinion would be very appreciated, Robert. I went ahead and posted a basic first exercise here. I thought about waiting, since it is so simple...but then decided that if there were a fundamental error in the most basic stuff, I should find out before making the same mistake in the more complex exercises. It's not much at this point, but I know I shouldn't skip ahead if I expect to get any benefit.

My instinct was to wait until I had a lot more of these done, but, I figured that it would be silly if there was a fundamental error in the more basic stuff which ruined everything more complex that followed. So, I'll post the first round of really basic ball bounces that I've been messing with. The goal is to work my way through basic exercises in an attempt to improve. Constructive critiques are encouraged (I am trying to get better)...thanks in advance for any pointers. This set of four starts with a ball drop without any squash and stretch, then a small amount of lateral movement is added, then squash and stretch is added and finally some roll is added. Once I'm pretty sure everything in these is working, I'll kick out another set. The ZIP file includes the model, Actions, Choreographies and shaded wireframe renders (everything is animated at 24 frames per second)...my thinking is that it will make it easier to find problems with what I'm doing. 01_ball_bounce_no_squetch_no_distance.mov 01_ball_bounce_no_squetch_with_distance.mov 01_ball_bounce_with_squetch_with_distance.mov 01_ball_bounce_with_squetch_with_distance_and_rotation.mov bouncing_ball_exercises_01.zip

I hate having to post a "stay alive" for this thread, but I got extremely busy the past couple of weeks. I did some CP Weighting on the guide bones to make sure my modeling was working on the generic character and made some modeling fixes (around the hips for better bending and upper arm to get rid of a "Michellin Man" effect). I have also done a few animating exercises to get myself a little practice (just some bouncing ball stuff which I'll expand upon over the next month or so, I'll post all of it when I get things to a point where I need some critiques) and did some modeling that isn't finished yet. I have never gone through all of the exercises I've seen with bouncing balls and I felt like it would be a good thing to do. I'm going to try to get something in a state where I can post it in the next week...could be several things if I'm lucky.

Incredible model, as usual, Stian!

You might have to contact Emilio Le Roux about an early version of sweeper.

Great stuff, Mike!

What image is on the CD? That would determine whether you can use v13 with it or not. If it's a white-haired Yeti, that would be v13, if it has a mostly silver Tinman with Scarecrow it is v14...the green Tinman with Scarecrow is v15. Hope that helps.