code: @Override
  	public void setFirstAxis(double x, double y, double z, double extent, CoordinateSystem3D system) {
  		this.axis1.set(x, y, z);
  		assert(this.axis1.isUnitVector());
  		if (system.isLeftHanded()) {
  			this.axis3.set(this.axis1.crossLeftHand(this.axis2));
  		} else {
  			this.axis3.set(this.axis3.crossRightHand(this.axis2));
  		}
  		this.extent1 = extent;
  	}
docs: Set the first axis of the second .
  The third axis is updated to be perpendicular to the two other axis.
  
  @param x
  @param y
  @param z
  @param extent
  @param system