calculateRotationAxis( vec1, vec2 ) {

		this._rotationMatrix.extractRotation( this._cameraMatrixState );
		this._quat.setFromRotationMatrix( this._rotationMatrix );

		this._rotationAxis.crossVectors( vec1, vec2 ).applyQuaternion( this._quat );
		return this._rotationAxis.normalize().clone();

	}
Calculates the rotation axis as the vector perpendicular between two vectors.

@private
@param {Vector3} vec1 - The first vector.
@param {Vector3} vec2 - The second vector.
@returns {Vector3} The normalized rotation axis.