Path Tracing technology advances in PC games, but natural environments remain a big headache. Between leaves, branches, partial transparency of vegetation, and the constant animation of thousands of elements, the workload explodes for real-time Ray tracing.
It is precisely on this point that Nvidia is working on a new foliage system for its RTX Mega Geometry designed for very dense scenes. Furthermore, this technology is not just a concept but actually usable as it is already associated with a highly anticipated game: The Witcher 4.
NVIDIA explains that they are working with CD PROJEKT RED to integrate this new approach. The goal is to make a world possible with fully path traced forests composed of detailed and animated vegetative elements.
RTX Mega Geometry, a scale change
Up to now, RTX Mega Geometry has been presented as a block capable of better managing complex geometry in Path Traced worlds. Nvidia explains that the approach involves compressing geometry into clusters for “intelligent” reuse as the scene unfolds. In theory, this would allow building Ray Tracing structures up to 100 times faster than previous methods. In practice, Alan Wake 2 benefits from an announced FPS gain ranging from 5 to 20% for a reduction of 300 MB of VRAM after integration into existing assets.
So, the novelty is the extension of this logic to dense vegetation. NVIDIA now talks about a system based on “partitioned top-level acceleration structures”. This is a method to chop up and update very large portions of a scene in each image without inflating the calculation cost.
It’s worth noting that NVIDIA also introduced an extension of the RTX Dynamic Illumination SDK with ReSTIR PT. This is an algorithm designed to improve the reuse of light paths at any bounce, with a particular focus on shiny surfaces and mirror reflections.
Caution still required
At this stage, we are dealing with a technology in development and not a finalized and testable feature in a commercially available game. We do not know what the real cost will be in terms of GPU, what concessions will be necessary on internal resolution, or to what extent these advancements will remain linked to the latest RTX ecosystem.
In fact, Nvidia has become a specialist in innovations explicitly associated with the latest GeForce cards. This reminds us that some blocks could first benefit the most recent cards.
