  A considerable limitation of employing sparse voxels octrees (SVOs) as a
model format for ray tracing has been that the octree data structure is
inherently static. Due to traversal algorithms' dependence on the strict
hierarchical structure of octrees, it has been challenging to achieve real-time
performance of SVO model animation in ray tracing since the octree data
structure would typically have to be regenerated every frame. Presented in this
article is a novel method for animation of models specified on the SVO format.
The method distinguishes itself by permitting model transformations such as
rotation, translation, and anisotropic scaling, while preserving the
hierarchical structure of SVO models so that they may be efficiently traversed.
Due to its modest memory footprint and straightforward arithmetic operations,
the method is well-suited for implementation in hardware. A software ray
tracing implementation of animated SVO models demonstrates real-time
performance on current-generation desktop GPUs, and shows that the animation
method does not substantially slow down the rendering procedure compared to
rendering static SVOs.
