At GDC 2019, NVIDIA’s Martin Stich walked attendees through ray tracing in 4A’s Metro: Exodus (available now) and Remedy’s Control (coming later in 2019) on PC. You can watch that excerpt of his talk here.
Prior Metro games took place in claustrophobic railway systems. Metro Exodus, by contrast, lets players step outside to explore an open world. Given this new direction, the developers chose to add dynamic global illumination to the game, focusing on light coming from the sun. “The game computes one bounce of indirect light from sunlight,” explains Stich. “Ray tracing here is used to compute an AO pass and a GI pass with the same ray, which are then added to the lighting terms that are already being computed for the raster passes.”
The end result is a more natural look, wherever sunlight can be observed. Take a look at the side-by-side comparison below. Scene elements that seem to ‘float’ in the “RTX OFF” screenshot look more grounded in the “RTX ON” screenshot. The white pillow (bottom right) is a good example. Light bounces as it would in real life; in the “RTX ON” version of this scene, light bouncing for the floor is captured on the red rubber ball (bottom center), and shadows obscure the soldier’s left boot (far right).
Remedy is a development team that has built a reputation for pushing the graphics envelope. Max Payne, Alan Wake, and Quantum Break are all groundbreaking works from a technical perspective. Control, their upcoming game, features ray traced shadows, ray traced reflections, and ray traced global illumination. Martin gives viewers an early look at how the game handles indirect diffuse lighting, indirect specular reflections, and contact shadows.
This video is just a small portion of an in-depth hour-long talked called GRAPHICS REINVENTED: RTX UPDATE, which can be found here. The full talk provides details about denoising, ray tracing with Unreal Engine and Unity, ray tracing developer tools, and DLSS (deep learning super sampling). An NVIDIA Developer Zone membership is required to access the full content; registration is free, and takes less than one minute to complete.