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by __s 3389 days ago
> After a few days of investigation, Sergey improved the layout of hair bounding boxes for BVH structure. What does this mean? A more in-depth explanation is coming soon.

Sounds more that they optimized their BVH implementation

1 comments

Sorry if I wasn't clear. Using a time-dependent BVH (where instead of two vec3 for the corners you store four, one pair for t=0 and one for t=1) is an "optimization". Given the later sentence:

> After that, he applied the same optimization to triangles (for actual character geometry)

it suggested that the bug was just using a single bounding box that ignored the motion (which is correct, but slow).