function PhysicsInstance( node, component )
{
	this.uid = LS.generateUId("PHSX"); //unique identifier for this RI
	this.layers = 3|0;

	this.type = PhysicsInstance.BOX; //SPHERE, MESH
	this.mesh = null; 

	//where does it come from
	this.node = node;
	this.component = component;

	//transformation
	this.matrix = mat4.create();
	this.center = vec3.create(); //in world space

	//for visibility computation
	this.oobb = BBox.create(); //local object oriented bounding box
	this.aabb = BBox.create(); //world axis aligned bounding box
}
PhysicsInstance contains info of a colliding object. Used to test collisions with the scene

@class PhysicsInstance
@namespace LS
@constructor