In this video, Alex discusses several notable presentations from Nvidia’s Game Developers Conference (GDC), focusing primarily on advancements in ray tracing and path tracing technologies. The first presentation highlighted is “The Future of Path Tracing” by Martin Stich and Carmelo Fernandez Aguerra, which details recent updates in DirectX Raytracing (DXR) API, including the integration of Shader Execution Reordering (SER) and Opacity Micro Maps (OMMs). These features, initially exclusive to Nvidia’s Ada Lovelace GPUs, are becoming standardized in DXR 1.2, enabling broader support across other GPU vendors like Intel and AMD. A significant application of these technologies is demonstrated in The Witcher 4, where Nvidia developed an LOD system combining OMMs and DXR mega geometry to efficiently path trace millions of trees with high detail.
The second major presentation covered is from Capcom and Nvidia, focusing on implementing real-time path tracing in Capcom’s RE engine, used in games like Resident Evil Requiem. Capcom engineers shared insights on the artistic and technical challenges of integrating path tracing, such as balancing visual fidelity with performance and ensuring artist satisfaction with the new lighting models. Interestingly, Resident Evil Requiem did not utilize Nvidia’s advanced SER technology but instead relied on custom compute shader optimizations. The presentation also discussed the use of guided buffers to maintain visual effects like rain and projected textures, which are crucial for stable and realistic rendering with ray reconstruction denoising.
Nvidia’s Kelvin Shu elaborated on optimizing path tracing performance in the RE engine, revealing that naïvely enabling SER could initially increase rendering times. However, through detailed optimizations, they reduced path tracing times significantly, from 17.7 milliseconds to 3.3 milliseconds. This optimization suggests that upcoming games like Pragmata might be the first to ship with DXR 1.2 and SER-enabled path tracing. Capcom also expressed ambitions to further enhance their path tracing capabilities by adding features such as direct illumination, transparent/translucent path tracing, volumetric effects, and neural shading, indicating a strong commitment to pushing high-end PC graphics forward.
A particularly interesting topic discussed is the current practice of using rasterization for primary visibility rays in most path-traced games, rather than tracing these rays directly. The presentation posed the question of when it might become advantageous to fully path trace primary visibility, highlighting potential benefits like improved effects in sniper scopes and wide field-of-view rendering without clipping issues. Performance comparisons across GPU architectures show that while rasterization remains more efficient on older GPUs, newer architectures like Ada Lovelace and the upcoming Blackwell narrow the performance gap, suggesting future titles might offer full path-traced primary visibility as an option.
Finally, Alex mentions other related presentations, including Nvidia’s work on hair rendering in the Indiana Jones game, where hair is fully path traced with primary visibility rays. He also teases upcoming discussions on neural texture compression and neural shading technologies from both Nvidia and Intel, which complement each other and promise further advancements in real-time rendering. Overall, these presentations showcase significant progress in path tracing technology, optimization strategies, and collaboration between hardware vendors and game developers to enhance visual fidelity in next-generation games.
