metalnessMap

The metalness map is a texture used in physically based rendering (PBR) workflows to define the metallic properties of a surface. It is typically a grayscale image where white represents fully metallic and black represents non-metallic, or dielectric. Intermediate shades of gray represent materials that have a mix of metallic and non-metallic properties, or surfaces with varying levels of micro-surface detail that affect specular reflections.

In PBR, the metalness value directly influences how light interacts with a surface. Metallic surfaces reflect light specularly without chromatic aberration, meaning the reflected light retains its original color. Dielectric surfaces, on the other hand, reflect light diffusely and can exhibit chromatic aberration, where the color of the reflected light is altered. The metalness map allows artists to control this behavior on a per-pixel basis, enabling the creation of realistic materials like brushed metal, weathered steel, or painted surfaces with metallic flakes.

The precise interpretation of the metalness map can vary slightly between different PBR rendering engines and workflows. However, the core concept remains the same: it's a crucial parameter for achieving physically accurate material representations by dictating the reflectivity and color response of a surface to light. Accurately authored metalness maps are essential for creating believable and consistent visuals in real-time rendering, game development, and visual effects.