Glossary

Normal Map

A texture that stores surface directions to fake fine detail without extra geometry.

A normal map is an RGB texture in which each pixel encodes a surface direction instead of a color. The shader lights the surface as if small bumps, seams and scratches were modelled, while the mesh itself stays simple. Game engines and glTF use tangent-space normal maps, which look mostly light blue-purple. A common pitfall is the green channel: OpenGL-style maps (glTF, Blender, Godot, Unity) have green pointing up, DirectX-style maps (Unreal) have it flipped. A map read in the wrong convention makes bumps look dented. Most engines offer a flip-green option for that. On Grab3D, all High Detail models and nearly all Lightweight models ship a normal map as part of their PBR set. The low poly models do without one: they are flat-shaded with a palette texture.