Glossary

PBR

Physically based rendering: materials that react to light in a consistent, realistic way.

PBR (physically based rendering) describes materials by physical properties instead of highlights tweaked by eye, so the same asset looks right under daylight, torchlight or an HDRI. The common metallic-roughness workflow (the one glTF uses and Unity, Unreal, Godot and Blender all support) combines a base color map (pure color without baked lighting), a roughness map (matte to glossy), a metallic map (metal or not) and a normal map for fine surface detail. Ambient occlusion and emissive maps are optional extras. On Grab3D, High Detail models ship all four maps as 4K textures in the download, and most Lightweight models ship the same set at 2K, with weathering baked into the textures. The low poly models are the exception: they use a single small palette texture.