A Free-Space Diffraction BSDF | NVIDIA Research

Key Takeaways

simulation is one of the best tools we have to understand the world and to create new worlds both virtual and real this paper presents a new approach for modeling wave defraction where waves spread out as they pass by object boundaries this IM shows the defraction of light through a small aperture while it's nice to have for rendering defraction is crucial to simulate at longer wavelengths for example with radar sound and radio waves our algorithm is highly accurate and is thousands of times more more efficient than the state-of-the-art it is the first model that can simulate defraction with complex geometry as a bonus our algorithm can be accelerated with GPU raid racing with our approach when a ray intersects a surface we examine the nearby geometry to see if it is close to an object boundary if not defraction is minimal and can be ignored if it is we compute the distribution of defract energy using mon Carlo integration we sample a single Ray that carries refracted energy and trace it from the aperture this image shows a simulation of radio wave propagation from an antenna on top of a building on the left given the long wavelengths of radio waves defraction around the building's edges is crucial to account for compare the energy distribution shown on the top our approach with the Distribution on the lower left which neglects defraction our approach captures a much more accurate result as is shown in the error image on the lower right here's a view of the same scene from above where we can see how much energy is missed with the ray Optics approach but is accurately simulated with ours thanks for watching