tetrahedral scan conversion

This chapter is less about marching rays and more about the problem underneath many ray-marching systems: how signed distance fields are built in the first place. It gives a clean definition of an SDF as a sampled grid of closest-surface distances with the standard negative-inside, positive-outside convention, then immediately turns to the hard cases that make real SDF generation difficult, such as thin regions, degeneracies, holes, and inconsistent meshes. That broader context makes it a strong citation when you want to explain that SDF rendering depends on representation quality, not only on the marcher.

What especially separates it from simpler introductions is the attention to sign correctness and failure modes. The chapter explains why naive plane-based sign tests leak, why enlarged bounded volumes can produce incorrect interior-exterior classification, and how pseudonormals and tetrahedral scan conversion fix those errors in a GPU-friendly pipeline. So while it is not the canonical article on sphere tracing itself, it is one of the best sources for explaining where signed distances come from, what can go wrong in computing them, and why robust SDF construction matters for downstream rendering and simulation.