The main goal of our research: to compare various modern lighting technologies, including RTXGI, RTX Reflections, LumenGI, Lumen Reflections and Legacy lighting technologies. We focused on analyzing performance and visual quality.
In the course of our research, conducted on visual quality for games on PC and current-gen console platforms, we discovered the potential of "RTXDI" from the Nvidia RTX Branch to significantly improve runtime visual quality of lighting, shadows, reflections and increase the performance while using hardware ray tracing in Unreal Engine 5.
To conduct our research, we used the latest version of Unreal Engine 5.3 from the NVIDIA RTX Branch (commit b7bb543). Our tests were carried out on hardware: RTX 3070, Ryzen 7700x, with 32 GB of DDR5 6400 RAM, ssd SATA 3, FullHD Monitor. We used the asset "Big Star Station LUMEN" from the Epic Games Marketplace to create a test scene.
For performance analysis, we used Unreal Insights and Stat Commands, also analyzing image quality, and testing was conducted in the project build. LumenGI and Lumen Reflections were configured at the engine level, with RTX shadows and “RTXDI” enabled. Work was also done to find console commands for optimization, toggling RTX, Lumen, and “RTXDI” quality settings, aided by the "Console Variables Editor Plugin." Looking at FPS and Stat Unit values, we recorded almost a twofold increase in FPS when using “RTXDI”, and GPU frame rendering time almost halved. With some optimization using console commands, FPS increased almost threefold, and GPU frame rendering time decreased by a factor of 2.5, albeit sacrificing a couple of milliseconds on the CPU. Preserving high image quality was an important aspect. We also tested the use of “Nanite” in conjunction with RTX and Lumen, but when “RTXDI” was enabled, we did not find any positive effects.
Testing was conducted in corridor and open locations. In the corridor location, at FullHD resolution, thanks to RTXDI and some CVars, we managed to increase the average FPS from 25 to 64, almost without sacrificing image quality.
As a result, we learned to optimize complex dynamic lighting with a large number of light sources with RTX shadows, LumenGI, and Lumen Reflections enabled, increasing the average frame rate by more than x2 and now able to create incredible lighting using modern technologies.
In the final result we are improving the quality and performance of Lumen Technologies using Nvidia technologies from the RTX Branch, compared to the default version of the engine. The potential of RTX technologies has reached the point where we were able to use them in corridor scenes in Unreal Engine 5, achieving incredible image quality while maintaining acceptable performance. Our research confirms the potential of the Nvidia technologies for optimizing lighting in Unreal Engine 5. These innovative systems represent significant progress in the field of realtime visualization and will undoubtedly play a key role in the future development of the gaming industry.