public double distance(Vector3 point){
  double xd=this.x - point.x;
  double yd=this.y - point.y;
  double zd=this.z - point.z;
  return Math.sqrt(xd * xd + yd * yd + zd * zd);
}

public double distance ( Vector3 point ) { double xd = this . x - point . x ; double yd = this . y - point . y ; double zd = this . z - point . z ; return Math . sqrt ( xd * xd + yd * yd + zd * zd ) ; }
returns the distance from this point to the given point .
