adding gravity?

[nooboflash]

how do you add gravity to a movie clip?

[dmonkey]

Oh boy that's a question and a half.

I'm hoping to write a tutorial on this at some point. Until then, look here (or wait for someone else to reply!).

[lezhang]

its really quite simple if you don't want anything fancy; flash has two axis, the y and x axis. but the axis is flipped, so the left top corner is 0,0. If you want gravity, then u just have to change the movieclip's position(y) by doing this:
...
_root.object_mc._y++;
...
if you put that on enterFrame then it will run constantly at every frame so the object will fall like you wanted it. It won't stop falling though, but i think you can figure out how to take care of that, just put in a conditional statement.

[Greatfaith]

Here's an example. I drew a ball, made it into a movieclip and added this code.

onClipEvent (load) {
	yspeed = 0;
	gravity = .3;
}

onClipEvent (enterFrame) {
	this._y += yspeed;
	yspeed = yspeed + gravity;
	
	if (this._y >= 400) {
		this._y = 400;
		yspeed *= -.7;
	}
}

This is just a basic example.