Ray tracing massive amounts of animated geometry using tetrahedral cages

a day ago

The AMD FidelityFX Hybrid Shadows sample combines ray traced shadows and rasterized shadow maps for high quality and performance.
The paper addresses the scaling problem of animated geometry in ray tracing by introducing tetrahedral cages.
A low-resolution tetrahedral cage is built around a static mesh; only the cage is animated each frame, while static mini-BLASes are reused.
This approach decouples animation cost from triangle count, reducing computational and memory overhead significantly.
The method renders roughly 585 million animated triangles at 60 fps on an AMD Radeon RX 9070 XT at 1080p.
It is ideal for connectivity-preserving animations such as swaying vegetation, grass, crowds, and distant characters.
Coarser cages minimize memory and cost; finer cages better approximate the original animation.
Tetrahedron-cage animations can work alongside DXR partitioned top-level structures and cluster level acceleration structures.
Future work focuses on improved cage generation, animation quality, and integration with modern ray-tracing pipelines.

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