What is PBR?

PBR means physically based rendering. The engine shades a surface from maps that describe the material, instead of painting highlights into the texture. The same wood, concrete, or steel then stays believable in sun, indoor lights, and night scenes. A standard PBR set has four maps. Base color, also called albedo, is the color with the light removed. Roughness controls how tight the highlight is: low roughness is glossy, high roughness is matte. Metallic tells the shader which parts are metal. The normal map fakes small bumps and edges without extra geometry. Some pipelines add height and ambient occlusion. TrimSheetFast exports those maps from one trim sheet, so a single atlas can shade many modular props in Unity, Unreal, Blender, and Godot.