Path Tracing technology is progressing in PC games, but natural environments remain a big headache. Between the leaves, the branches, the partial transparency of the vegetation and the permanent 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 a concept but rather usable since it is already associated with a highly anticipated game: The Witcher 4.
NVIDIA explains that it is working with CD PROJEKT RED to integrate this new approach. the goal is to make possible a world with fully path traced forests composed of millions of detailed and animated plant elements.
RTX Mega Geometry, a change of scale
Until now, RTX Mega Geometry was presented as a brick capable of better managing complex geometry in Path Traced worlds. Nvidia explains that the approach consists of compressing the geometry into clusters for so-called “intelligent” reuse as you move through the scene. On paper, this would allow Ray Tracing structures to be built up to 100 times faster than previous methods. In concrete terms, Alan Wake 2 benefits from an announced FPS gain of between 5 to 20% for a reduction of 300 MB of VRAM after integration with existing assets.
The novelty is therefore the extension of this logic to dense vegetation. NVIDIA is talking this time about a system based on “partitioned top-level acceleration structures“. This is a method for slicing and updating very large portions of a scene each frame without exploding the computational cost.
Note that NVIDIA also presented an extension of the RTX Dynamic Illumination SDK with ReSTIR PT. This is an algorithm intended to improve the reuse of light paths at any bounce, with a particular focus on shiny surfaces and mirror reflections.
Prudence tout de même
At this stage, we are facing a technology in development and not a finalized and testable functionality in a commercial game already available. We don’t know what the real cost will be on the GPU side, what concessions will be necessary on internal definition, nor to what extent these advances will remain tied to the newer RTX ecosystem.
Indeed Nvidia has become a specialist in new products explicitly associated with the latest GeForce. This reminds us that certain bricks could first benefit the most recent cards.
