Nvidia’s RTX Mega Geometry is being used both to optimize existing ray-traced content and to trace more detailed meshes. Hardware tester Dan Mateescu reported memory savings in an Alan Wake 2 version comparison, while his RTX Bonsai Diorama Demo tests found more complete shadows and reflections at the cost of lower frame rates.
How Mega Geometry handles dense scenes
Nvidia introduced its first GeForce RTX graphics cards in 2018, when Battlefield V used ray tracing for reflections. Control added multiple ray-traced effects in 2019, while Quake II RTX and Cyberpunk 2077 adopted path tracing, which samples light paths to simulate lighting across a scene. Geometry systems such as Unreal Engine 5’s Nanite have also enabled increasingly detailed game assets.
Ray tracing uses acceleration structures, commonly organized as bounding volume hierarchies, or BVHs, to identify which surfaces a ray can hit. Updating those structures can become costly in scenes containing dense, animated geometry. Developers can reduce the workload with simplified proxy meshes, but differences between those meshes and the visible scene can produce incomplete reflections, missing shadows and incorrect self-occlusion.
Mega Geometry introduces an optional Cluster Acceleration Structure, or CLAS, using batches of up to 256 triangles designed for GPU-driven processing. Nvidia describes the technology as compressing geometry into clusters and reusing them between frames to accelerate construction of ray-tracing structures. Developers can use it to optimize existing content or make more detailed geometry available to the renderer.
Nvidia says Mega Geometry supports RTX GPUs dating back to the RTX 20-series. The Blackwell-based RTX 50-series adds dedicated triangle cluster intersection and compression engines in its fourth-generation RT Cores.
Alan Wake 2 optimizes existing content
Remedy Entertainment added Mega Geometry to Alan Wake 2 in PC update 1.2.8 in early 2025. Remedy’s update notes describe improvements to ray-tracing CPU and GPU load, VRAM use and image quality, and say the feature is automatically enabled on all RTX GPUs with up-to-date drivers. Nvidia describes the implementation as an optimization of BVH construction and updates.
Comparing versions 1.2.7 and 1.2.8 on an RTX 4090 in early 2025, Mateescu reported about 1 GB less VRAM use and a 13% performance increase at both native 4K and 4K output with DLSS Quality, using maximum settings and path tracing. Those figures describe a version comparison across an update that also changed DLSS and ray-tracing features.
Nvidia separately cited a 5–20% frame-rate improvement and a 300 MB VRAM reduction in Alan Wake 2. Those company figures are distinct from Mateescu’s reported measurements.
Bonsai traces more detailed meshes
The RTX Bonsai Diorama Demo uses Mega Geometry to make full-detail Nanite meshes available to the path tracer. Built with Nvidia’s RTX branch of Unreal Engine 5.6, it also includes RTX Dynamic Illumination, DLSS Super Resolution, DLSS Ray Reconstruction and DLSS Frame Generation. Mega Geometry can be switched on and off for comparison.
Mateescu’s image comparisons showed missing leaves in reflections and incorrect self-occlusion on a tree with Mega Geometry disabled. Enabling it restored the reflected detail and corrected the self-occlusion in those examples. He also reported more complete shadows where simplified geometry had omitted fine shapes.
Tracing the additional geometry reduced frame rates. On an RTX 5090, Mateescu reported performance declines of 23% at 1080p, 24% at 1440p and 21% at 4K with Mega Geometry enabled. Performance remained above 60 frames per second at rendering resolutions of 1080p and 1440p.
On an RTX 5070, the reported declines were 27% at 1080p and 26% at 1440p. Mateescu said reaching 60 FPS with Mega Geometry enabled required frame generation or DLSS with an internal rendering resolution below 1080p.
Mateescu reported that the demo’s developer guide listed the RTX 5060 as its recommended GPU. In his tests, the card averaged below 30 FPS with Mega Geometry enabled and DLSS Super Resolution and Frame Generation disabled. With both DLSS features enabled at 1080p, he reported more than 100 FPS, a figure that includes generated frames. He also described compromises in image quality and input latency.
Foliage plans for future games
At GDC 2026, Nvidia said Mega Geometry would feature in Control Resonant and that CD Projekt Red planned to bring its in-development foliage technology to The Witcher 4. Nvidia says the foliage system uses partitioned top-level acceleration structures to manage dense environments containing animated vegetation.
In its path-tracing presentation, Nvidia described selectively updating relevant portions of a scene as the camera moves and using Opacity Micromaps for distant levels of detail to reduce memory requirements.
Nvidia’s reported forest demonstration covered 5 km by 5 km and contained roughly 60 million plants across more than 200 species, including around 1 million trees. The company described fully dynamic, path-traced lighting, with all assets resident in memory rather than streamed and fine foliage details represented as geometry.
The company’s reported performance figures were about 80 FPS on an RTX 5090 at 4K output with DLSS Quality, rendering internally at 1440p, and about 58 FPS on an RTX 4070 at 1440p output with DLSS Quality, rendering internally at 960p. These were technology-demonstration figures rather than performance results from The Witcher 4.
