Real-time Lighting from Complex Luminaires

Simulating the lighting from complex luminaires in real time is difficult due to their constituent elements, which alter the path of light from the source to the device's exit. This is particularly true for historical luminaires such as lanterns and street lamps, which use antique glass whose distortions produce caustic effects that are difficult to reproduce. In this paper, we present a method for pre-calculating the illumination produced by any type of luminaire in its surrounding volume, preserving its high-frequency details such as caustics and storing it in a Neural Radiance Cache (NRC). This cache is independent of the 3D environment in which the luminaire is placed and can therefore be used in any 3D rendering project. We also propose an implementation of our approach in the Unreal Engine real-time 3D creation tool , in the form of a material, which allows our NRC to be used without modifying the 3D engine and provides interactive and realistic rendering of the results.