extractBasis( xAxis, yAxis, zAxis ) {

		xAxis.setFromMatrixColumn( this, 0 );
		yAxis.setFromMatrixColumn( this, 1 );
		zAxis.setFromMatrixColumn( this, 2 );

		return this;

	}
Extracts the basis of this matrix into the three axis vectors provided.

@param {Vector3} xAxis - The basis's x axis.
@param {Vector3} yAxis - The basis's y axis.
@param {Vector3} zAxis - The basis's z axis.
@return {Matrix4} A reference to this matrix.