Wider generality relation in the road lighting calculation

The design of the outdoor lighting is based on the point-by-point method to estimate the direct component of the illuminance and it has a high complexity. This complexity is higher as the spatial repartition of the luminous intensities is more asymmetrical and as the more random is the position between the luminaire and the visual task. At the present, the lighting-domain specific software helps for quick and precise calculus, using some complex formulas with different degrees of generality. The present paper proposes a new way in applying the point-by-point method, by a different estimation of the zenith (a) and azimuth (P) angles. It uses an orthogonal reference system placed in an arbitrary point, which is transformed by successive rotations into a more convenient one. Using this new method, the resulted relations have a higher generality and the calculus time is shorter, especially in the very complex systems. Even seem apparent complicated, the obtained formulas are a result of the calculus with rotation matrices and can be easy implemented into the software. Moreover, they can be easily customized for any specific conditions.