MeshPhysicalMaterial

MeshPhysicalMaterial is a material class in Three.js that extends MeshStandardMaterial to provide advanced physically based rendering (PBR) features. It models how light interacts with real‑world materials by combining albedo color, roughness, metalness, and a range of additional properties. It supports both opaque and translucent surfaces and is commonly used for glass, metals, plastics, and fabrics.

Key features include a separate clearcoat layer for an extra glossy coating, transmission for light that passes through the material, and thickness to control absorption and refraction. Clearcoat options enable a second specular highlight and a layered look without changing the base color. These features allow more realistic surface detail and light interaction, particularly for multi‑layered materials.

Other enhancements are the fabric‑like sheen effect, which adds a subtle glow on certain materials, along with controllable roughness for the sheen. Attenuation and attenuation maps model how light is absorbed as it travels through thick materials, while IOR (index of refraction) determines how light bends during transmission. Transmission, thickness, and IOR work together to create glass‑like or translucent appearances.

MeshPhysicalMaterial shares the standard texture channels with MeshStandardMaterial, such as map (diffuse), roughnessMap, metalnessMap, normalMap, aoMap, emissiveMap, and envMap for image-based lighting. It is more computationally demanding than simpler materials but yields higher fidelity for realistic light transport and surface layering.

Usage notes: configure roughness and metalness for basic PBR behavior, adjust transmission and thickness for translucency, and use environment maps to enhance reflections and refractions. The material is well suited to realistic renderings involving complex light paths and layered surface properties.