Pixelcounter

Fast and Robust External Solar Shading Calculations using the Pixel Counting Algorithm with Transparency

Project Details
  • Title: Pixelcounter
  • Date: August 8, 2017
  • Link: Pixelcounter

External solar shading calculations play an important role in energy models for buildings. Current simulation software implements polygon clipping algorithms for these calculations. However, polygon clipping suffers from several limitations, such as high computational costs and, for complex geometry, robustness issues.

These weaknesses are a major bottleneck for the simulation of large scale urban building energy modelling (UBEM). This paper introduces a graphics hardware accelerated shading algorithm that uses pixel counting and supports transparency. The algorithm has been integrated in EnergyPlus and proves to be on average 2 times faster than EnergyPlus's shading algorithm, while maintaining an accuracy of 0.01.