I was looking at the Leo Burnett Big Ideas come out of Big Pencils site and its use of a 3D camera and realised a whole year had gone by since I last posted 3D camera zooming and panning scripts. I also realised that my code had changed throughout the year to better reflect the 3D reality.  This post is a word out to the  3D zoom menu, the 3D perscpective and pull trhrough posts. 

What has changed in the code is the way I interpret 3D.  As you can see, I have  added a clip property called ._z which represent the current position on the z axis, whereas the .z property is the original position of the clip.  Here is the new 3D pull & camera Zoom core equations :

	// Calculating actual scale values according to scale = fl/(z+fl) formula
	var scale = focalLength/(focalLength+this._z);
	
	// Position
	this._x = centerX + scale*(oCamera.dx - this.x);
	this._y = centerY + scale*(oCamera.dy - this.y);
	this._z = centerZ + (oCamera.dz - this.z);

	// x|y scale
	this._xscale = scale * 100 ;
	this._yscale = scale * 100 ;
	
	// transparency
	this._alpha = scale * 100 ;