main/src/georegression/geometry/ConvertRotation3D_F64.java
public static DMatrixRMaj rotZ( double ang, DMatrixRMaj R ) {
		R = checkDeclare3x3( R );

		setRotZ( ang, R );

		return R;
	}
public static DMatrixRMaj rotZ( double ang, DMatrixRMaj R ) {
		R = checkDeclare3x3( R );

		setRotZ( ang, R );

		return R;
	}
public static DMatrixRMaj rotZ ( double ang , DMatrixRMaj R ) { R = checkDeclare3x3 ( R ) ; setRotZ ( ang , R ) ; return R ; }
Creates a rotation matrix about the z-axis.

@param ang the angle it rotates a point by in radians.
@param R (Output) Optional storage for rotation matrix.  Modified.
@return The 3 by 3 rotation matrix.
Creates a rotation matrix about the z - axis .