distance primitives

This article is effectively the working vocabulary of procedural SDF modeling. Instead of focusing on one renderer or one derivation, it collects distance formulas for primitives, modifiers, and operators in a form that can be dropped directly into shader code. For anyone building scenes, this is the page that turns the abstract idea of signed distance modeling into an extensible parts library: boxes, capsules, tori, repetitions, extrusions, smooth unions, and many other ingredients all presented in a compact, composable style.

What makes it particularly valuable is that it distinguishes between exact distance fields and conservative bounds. That distinction is easy to skip in beginner material, but it is crucial for understanding why some formulas march more reliably than others and why a locally cheaper approximation can create a worse global result by degrading step quality. In other words, Quilez is not just listing formulas; he is teaching the practical contract between modeling code and the marcher that consumes it.