Memory-Conserving Bounding Volume Hierarchies with Coherent Raytracing

Bounding volume hierarchies (BVH) are a commonly-used method for speeding up ray tracing, but they can consume a large amount of memory for complex scenes. We present a new scheme for storing BVHs that reduces the storage requirements by up to 79%. This scheme has significant computational overhead, but this can be reduced to negligible levels by shooting bundles of rays through the BVH (coherent ray tracing). This gives the speed of a coherency-based ray tracer combined with large memory savings, permitting rendering of larger scenes and reducing the cost of a hardware ray tracer.