Bouncing ball effect

[wizkidweb]

I'm making a tennis game and I was wondering how I can make a bouncing ball effect. I'm currently using the Alpha Channel Object , but I don't know how to make the illusion of the ball rising in the air, and then hitting the ground and bouncing back into the air.

Does anyone know how I can achieve this?

[Random]

Well first of all we'd have to know what perspective you use..

Top down?
Side view?
From behind?
Isometric?
3D?

[wizkidweb]

Oh right, sorry. It's top down view.

[Anders]

You can easily set the scale to:
[color:#3366FF]1.0 + abs( cos( <some-value> ) )[/color]

where <some-value> is 0 when the ball is down at the ground and 90 when it is closest to the camera. You can always add 1 or any other number that looks good to <some-value> and you will get a bouncing effect that just keeps on going.

If you want to make the ball bounce lower and lower over time, you could multiply the value you add to 1.0 with some value between 0 and 1.
For example:
[color:#3366FF]1.0 + abs( cos( <some-value> ))*jumpcoeff[/color]
You can then alter the "height" of the jump by changing the jumpcoeff value to whatever you like.

[wizkidweb]

OK thanks. I do have some questions though:

1) How would you define <some-value> and with what would you define it with?

2) What command should I use with this expression?

[Anders]

Well just replace [color:#3366FF]<some-value>[/color] with [color:#3366FF]value("MyCounter")[/color] or something similar. Any value you can change is perfectly suitable

I believe the Alpha Channel Object has a "Set Scale" action or something like that. Otherwise the Active Object in MMF2 has such an action now.

[wizkidweb]

Thanks! That wasn't exactly what I was looking for, but I think this effect suits it just fine.