# PBR Textures & Topology Basics

**Track:** 3D — beginner → intermediate — Generative AI 3D — proposed
**Framework / surface:** ij8 Studio (textured output + viewer)
**Level:** Intermediate
**Prerequisites:** Shape, Then Texture

**In one line:** Diffuse/roughness/metallic/normal; tris vs quads; polycount.

## Theory, aesthetics & inspiration

Physically based rendering splits a surface into separable channels: base color (diffuse) holds pigment free of lighting; roughness governs whether reflections are sharp or diffuse; metallic flags conductors; and a normal map fakes fine relief by perturbing how light bounces, without adding polygons. Together they let one material respond honestly under any lighting, the goal of Burley's principled model. Topology is the mesh's underlying weave: triangles render universally, but clean quads flow into orderly loops that deform predictably and subdivide cleanly (the Catmull-Clark tradition). Polycount is a budget — real-time work spends polygons where silhouette and motion demand them, and saves them on flat, hidden, or distant surfaces.