I'm curious as to whether or not there is a way to build Embree using OBBs as the default bounding entity for the BVH4/8 or even a small patch which would allow this.
We use oriented bounding boxes for curves and hair, but have no support for other primitives. This can also not easily be switched somewhere, as we use quite specialized code to select the orientation of the OBBs for curves.
Thanks for the quick reply! Are AABBs used exclusively for Tri/Quad/etc. geometries because of the kind of tessellations typically used for rendering?
AABBs work very well for triangles and quads. Curves are long and thin structures which cannot be bound tightly with AABBs, which is why we use OBBs in this case.