Quick way to do a bounce effect?

mickbadal wrote on 6/11/2007, 1:48 PM

I want to make a still "bounce" on the screen. I know I can use pan/crop and set keyframes, but as everyone knows something bouncing is not a linear motion; the object accelerates and decelerates. So simply setting a keyframe every 1/4 second and moving the ball to the top and bottom of the screen at each keyframe will not look like a "bounce". Yet trying to manually set the keyframes to create realistic-looking accel/decel can be a very time-consuming task.

Is there a quick way to add this kind of effect to an object over a specified duration in VMS? I've believe it may be called the "ease in" & "ease out" effects?

Thanks!
Mick

Comments

Tim L wrote on 6/11/2007, 2:56 PM

I'm not sure about the best way to do this (simulate a bounce).

However, I will point out that keyframes can be set to several different types: linear, smooth, fast, slow, hold, etc. (the exact names escape me, and I'm not at a computer with VMS installed). Right-click on a keyframe diamond to see the options.

The differances have to do with how the keyframed value changes over time from point A to point B.

For example, if the keyframes were 10 frames apart, and some value changed from 100 to 200 over that time, the "Linear" option would successively change to 110, 120, 130, 140, etc. -- the same amount of change from one frame to the next -- until it hit 200 on the 10th frame.

The "Fast" option (if that's what it's called) would make big changes initially, then taper off. Perhaps 100 --> 130, 148, 162, 175, 185, 191, 195, 198, 199, 200. So motion would start out fast, then ease into the final position. (This is just a completely ficticious example.)

Likewise the "Slow" option would start out slow, and accellerate toward the ending position.

So you might play with a mix of fast and slow keyframes to help simulate gravity. Fast for rising motion, then Slow for falling motion.

I haven't tried this myself, so I hope it works for you.

Tim L

mickbadal wrote on 6/12/2007, 7:05 AM

Tim, you hit the nail on the head, that's exactly what I was looking for! I'll play with those features a bit to come up with some good "ball bouncing" templates.

Thanks,
Mick

Chienworks wrote on 6/12/2007, 9:47 AM

Something else to consider, though it will be quite a bit more work ... the typical cultural illustration of a bounce shows the object getting taller and thinner near the top of the arc and squished short & fat at the bottom of the bounce. If you turn off maintain aspect ratio for pan/crop you can use keyframes to modify the image shape. You could then make it change from skinny to fat and back during each bounce.

Hokey? Yes. But it might add a bit to the effect.

mickbadal wrote on 6/12/2007, 10:34 AM

I like that idea - I'll try it.

Thanks