public Pos3D rotateYaw(double yaw){
  double yawRadians=Math.toRadians(yaw);
  double x=xPos;
  double z=zPos;
  if (yaw != 0) {
    xPos=x * Math.cos(yawRadians) - z * Math.sin(yawRadians);
    zPos=z * Math.cos(yawRadians) + x * Math.sin(yawRadians);
  }
  return this;
}

public Pos3D rotateYaw ( double yaw ) { double yawRadians = Math . toRadians ( yaw ) ; double x = xPos ; double z = zPos ; if ( yaw != 0 ) { xPos = x * Math . cos ( yawRadians ) - z * Math . sin ( yawRadians ) ; zPos = z * Math . cos ( yawRadians ) + x * Math . sin ( yawRadians ) ; } return this ; }
rotates this pos3d by the defined yaw value .
