Render Millions of Direct Lights in Real-Time With RTX Direct Illumination (RTXDI)

Until today, artists had performance constraints that artificially limited lighting complexity; real-time renderers simply could not support more than a handful of dynamic lights. For years, NVIDIA sought methods to remove this barrier and enable real-time rendering of arbitrarily complex lighting. With NVIDIA’s Marbles at Night demo shown at the launch of the Ampere GeForce GPUs, we achieved that goal.

Recent research building to this demonstration includes papers published at High Performance Graphics 2019 and ACM SIGGRAPH 2020. The authors promised the impossible: artists could create scenes with shadows from an enormous number of area lights on a consumer-grade GPU.

In 2021, we will be bringing this technology to game developers as RTX Direct Illumination, or RTXDI.

Complex night scenes in computer-generated films attain a grounded, photoreal look by simulating lights simultaneously; for example, a night amusement park. RTXDI makes this level of lighting complexity possible in real-time on a single NVIDIA RTX GPU, all while using a very limited ray budget. Traditionally, game developers baked most lighting and supported a small number of dynamic “hero” lights. RTXDI is a solution that offers far greater creative flexibility.

RTXDI efficiently renders visually complex scenes requiring numerous simultaneous light sources.

In addition to making game environments more beautiful, RTXDI also delivers significant process benefits to developers. For instance: Using true geometry for lights means that there is no further need for fake proxies. Hero lights are now a thing of the past, since every light in RTXDI is a shadow caster. And RTXDI tells the renderer exactly where to send shadow rays, speeding up their art pipeline.

“RTXDI is a big step towards photorealistic game renderers that provide artists with creative freedom to place as many lights as they like while maintaining near-constant real-time rendering performance,” says Alexey Panteleev, Principal DevTech Engineer at NVIDIA.

Learn more about how you can be among the first development teams to integrate RTXDI by going to the RTXDI Page.

If you are attending GTC Digital, RTXDI is discussed at length in the on-demand webinar, “Rendering Games with Millions of Ray-Traced Lights”.