Utils3D.projectVectors

[Flash CS4]

What matematics used in projectVectors?
Anybody know?

And why this matrix work with projectVectors
projMatrix= new Matrix3D(Vector.<Number>([1,0,0,0, 0,1,0,0, 0,0,1,0.0015, 0,0,0,1]));

but this don't work
perspective=new PerspectiveProjection ;
perspective.fieldOfView=45;
perspective.focalLength=400;
perspective.projectionCenter=new Point(0,0);
projMatrix= perspective.toMatrix3D();
trace(projMatrix)=>
[400,0,0,0, 0,400,0,0 ,0,0,0.25, 1,0,0,0,0]


Why 400? Why rawData[15]==0? Where 1