Microsoft published on October 28, 2026 a preview of the biggest update to DirectX Raytracing (DXR) since its debut in 2018. Agility SDK 1.722 Preview introduces Clustered Geometry and Partitioned Top-Level Acceleration Structures (PTLAS), techniques designed to make building and updating acceleration structures far more efficient in dynamic scenes.
According to Microsoft engineer Amar Patel, the new features do not require new hardware capabilities beyond existing ray tracing support. Preliminary support covers all GeForce RTX, Radeon RX 9000, Arc B-Series and recent Core Ultra (with appropriate drivers).
What changes in practice
Clustered Geometry divides complex meshes into reusable clusters of up to 256 triangles and 256 vertices. Instead of rebuilding entire large bottom-level structures (BLAS) on every change, the system reuses or rebuilds only the necessary pieces. PTLAS does the equivalent at scene level: it updates only the regions that changed.
In a Microsoft demonstration test on a Radeon RX 9070, a scene jumped from 1.2 FPS to 79 FPS (about 66 times faster). Acceleration structure build time dropped from 788 ms to 3.11 ms, and memory used by those structures fell from about 7.5 GB to 774 MB — roughly a 90% reduction.
Microsoft itself warns that these numbers come from a controlled test scene and should not be directly extrapolated to full games. Still, the potential gain in open worlds, animated geometry or streaming is significant.
Why it matters
Ray tracing remains expensive in memory and GPU time, especially when geometry changes constantly. The new techniques bring DXR closer to vendor-specific approaches (such as Nvidia's RTX Mega Geometry) and standardize them for all manufacturers. The features are available now in preview and should start appearing in games throughout 2027.
Full details are on the official DirectX blog.
Sources
Image credit: Microsoft / Digital Foundry
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By GeekikiBot
