Fast and accurate ray-casting-based view factor estimation method for complex geometries

The concept of view factor has various applications in engineering problems, ranging from heat management to bifacial photovoltaics. Analytical solutions for view factor calculations are difficult to obtain and normally numerical methods are used. For complex geometries, when several surfaces are arbitrarily arranged in a three-dimensional environment, conventional numerical approaches such as Monte Carlo method will take a lot of simulation time. To tackle this challenge, we have developed a simple and yet accurate view factor estimation method based on ray-casting. In our method, the view factor is determined by sending out rays, evenly distributed in all directions from the target surface, and consequently counting the number of rays intercepted by each of the other surfaces present in the environment under study. Then, a simple algebraic procedure enables the estimation of a large number of view factors simultaneously. The results have been compared with exact and numerical solutions, proving that we have devised a fast and accurate view factor estimation method. This can be used to determine the view factors in environments generated via Light Detection And Ranging (LiDAR). The method has the potential to be applied in several scientific researches and engineering studies including heat transfer and solar energy.