Combining 2DPath and 2D Physics

[jeroen.delau]

Hey! I'm trying to get 2DPhysics and 2DPath plugins to work together. But when I run the code nothing moves. The code commented out is working, I just want to add the physics to it.

var time:int;
var length:Number;
			
_moving = false;
_animation = false;
			
_path = new LinePath2D(getPoints());
length = _path.totalLength;
if(!_time){
	_time = length / _speed;
}
_path.addFollower(this.entity);
//_activeTween = TweenLite.to(_path, _time, {
				
//	progress:1, 
//	ease:Power0.easeOut,
//	onComplete: onComplete
//});
			
_activeTween = TweenLite.to(_path, _time, {physics2D:{velocity:0, angle:90, acceleration:200, friction:0}, onComplete:onComplete});

[jeroen.delau]

I found the problem! Stupid mistake, I forgot to add progress: 1, to the new statement. However, I'm currently encountering a new issue. Quite frequently the tween "over shoots". With the entities entities ending up beyond the prescribed path.

[GreenSock]

Those concepts are mutually exclusive. In other words, physics2D would need to control x/y properties in a specific way and yet the LinePath2D also controls them, but not in the same way. You could certainly tween the "progress" in a physics-based way I suppose, but as you discovered that means you're at the mercy of physics in terms of where/when it lands, although you could tweak the acceleration/friction/velocity values to try to get it just right. If your goal is to start at a specific velocity and then drift to a stop, ThrowPropsPlugin may be exactly what you're looking for, and it allows you to define a specific stopping point to ensure there's no "overshoot". 

[jeroen.delau]

Hmm, that is a bit of a bummer. I'm aiming to achieve a drop like effect. Start from stand still, accelerate to a max velocity, complete stop when the end of the path is reached. For ease of understanding, imagine Candy Crush dropping candy.

 

The path2D is working beautifully, but I can't get the right easing effect to mimic the gravity. Essentially it needs to accelerate to a constant speed and then stay level. Should I write a custom easing function instead?

[GreenSock]

When you said "accelerate to a constant speed and then stay level", I instantly thought of just using a regular tween with ease:Linear.easeNone but start it with a timeScale of 0.0001 (or something really small) and then use ANOTHER tween to tween that tween's timeScale to 1, thus it appears to accelerate. Kinda like:

var tween = TweenLite.to(....{ease:Linear.easeNone});
tween.timeScale(0.0001);
TweenLite.to(tween, 1, {timeScale:1, ease:Power1.easeIn});

Just an idea. 

[jeroen.delau]

Tweening the tween! Super clever, it works like charm.