public static Vector3d createDirectionRad(double theta, double phi) {
        final double f = TrigMath.sin(phi);
        return new Vector3d(f * TrigMath.cos(theta), f * TrigMath.sin(theta), TrigMath.cos(phi));
    }
public static Vector3d createDirectionRad(double theta, double phi) {
        final double f = TrigMath.sin(phi);
        return new Vector3d(f * TrigMath.cos(theta), f * TrigMath.sin(theta), TrigMath.cos(phi));
    }
public static Vector3d createDirectionRad ( double theta , double phi ) { final double f = TrigMath . sin ( phi ) ; return new Vector3d ( f * TrigMath . cos ( theta ) , f * TrigMath . sin ( theta ) , TrigMath . cos ( phi ) ) ; }
Gets the direction vector of a certain theta and phi in radians. This uses the standard math spherical coordinate system.

@param theta in radians
@param phi in radians
@return the direction vector
Gets the direction vector of a certain theta and phi in radians . This uses the standard math spherical coordinate system .