UE5 Materials: PBR Basics and 15 Surfaces, Explained

Base Color

The surface’s intrinsic color (albedo) with NO lighting, shadows or highlights baked in — the renderer adds those. Dielectrics use their diffuse color; pure metals put their reflectance tint here (gold’s yellow lives in base color).

Roughness

How microscopically rough the surface is, 0 (mirror-sharp reflections) to 1 (fully diffuse). This channel carries most of a material’s character — wear, smudges, wet patches and polish are all roughness stories.

Metallic

Effectively a binary switch: 1 for bare metal, 0 for everything else. Values in between are only for transition pixels (rust edges, paint chips). A half-metallic surface is almost always a mistake.

Normal

Per-pixel surface direction — fake geometric detail like pores, seams and dents that catches light without extra polygons. Detail belongs here or in displacement, never painted into the base color.