AMD has shown a ray tracing trick that slashes memory and acceleration-structure costs while keeping hundreds of millions of animated triangles moving in real time.
AMD Fellow Holger Gruen demonstrated the technique using a terrain scene containing about 25,000 independently animated plants. At maximum level of detail, the vegetation represents roughly 2.8 billion triangles.
After level-of-detail selection, the system ray-traces about 500 million animated triangles each frame using primary and shadow rays. AMD says the scene runs at more than 60 FPS at 1080p on a Radeon RX 9070 XT.
The clever bit is a tetrahedral cage wrapped around dense geometry. Traditional ray tracing requires independently animated objects to maintain and update their own Bounding Volume Hierarchies, or BVHs, which becomes painfully expensive as scenes grow.
AMD instead encloses complex geometry inside a much simpler deformable tetrahedral cage. The dense mesh and its BVH remain static and reusable, while only the surrounding cage animates.
During rendering, rays are transformed back into the geometry’s original reference frame before intersection testing. Animation costs therefore scale with cage complexity rather than the number of triangles buried inside it.
AMD’s cage-based demonstration used about 1.7GB of BVH memory and required roughly 3.3ms per frame for BVH updates. Updating conventional dense triangle bottom-level acceleration structures for the same scene could consume up to 80GB and take more than 300ms per frame on the same Radeon RX 9070 XT.
That works out to roughly 47 times less acceleration-structure memory and more than a 90-fold reduction in BVH update time, while handling the same 500 million animated triangles.
However, Tetrahedral cages surrender precise control over every individual vertex, making them better suited to grass, foliage, crowds and distant characters than animations requiring finely controlled deformation or changing mesh topology.
The work remains research, not something gamers can switch on tomorrow. AMD’s underlying paper, with the catchy title Ray Tracing Massive Amounts of Animated Geometry, won third place in the Wolfgang Straßer Best Paper Award at High-Performance Graphics 2026, while the company is preparing DirectX Raytracing samples and a header-only C++ library for developers.
