||A curved surface as well as bends of hollow light guides both cause the light field is transformed in a complex way between a light exit surface and light entrance surface. Most of light-guide models fail in reproducing illuminance patterns under varying atmospheric conditions including cloud fields formed into non-static arrays. The effect of broken clouds on light field bellow the light guide will be the first time treated in its complexity in this project. We will qualify and quantify the effect of bends and their positions on the light-pipe effectiveness, while the theoretical and numerical results will be applied in predictions of illuminance distribution at a workplane. The targeted optical experiments in a local atmosphere are aimed i) to prove the solution concept as well as ii) to identify the effects of different cloud types on light guide optical properties. This should improve the accuracy of optical modeling in different localities accepting prevailing types of clouds and turbidity conditions.