KHRMaterialsIridescence

KHR_materials_iridescence defines iridescence (thin film interference) on a PBR material.

Figure: Varying levels of iridescence IOR values. Source: Khronos Group.

Iridescence describes an effect where hue varies depending on the viewing angle and illumination angle: A thin-film of a semi-transparent layer results in inter-reflections and due to thin-film interference, certain wavelengths get absorbed or amplified. Iridescence can be seen on soap bubbles, oil films, or on the wings of many insects. With this extension, thickness and index of refraction (IOR) of the thin-film can be specified, enabling iridescent materials.

Properties:

• Iridescence

Example

The KHRMaterialsIridescence class provides a single ExtensionProperty type, Iridescence, which may be attached to any Material instance. For example:

import { KHRMaterialsIridescence, Iridescence } from '@gltf-transform/extensions';

// Create an Extension attached to the Document.
const iridescenceExtension = document.createExtension(KHRMaterialsIridescence);

// Create an Iridescence property.
const iridescence = iridescenceExtension.createIridescence()
    .setIridescenceFactor(1.0)
    .setIridescenceIOR(1.8);

// Attach the property to a Material.
material.setExtension('KHR_materials_iridescence', iridescence);