threejs-lighting

To configure Three.js lighting, you combine AmbientLight and DirectionalLight for base illumination, enable shadow maps for shadows, and add environment maps for Image-Based Lighting (IBL) reflections. This approach covers accurate shadows, ambient illumination, and realistic reflections in real-time rendering.

Image-Based Lighting (IBL) in Three.js uses environment maps to calculate ambient illumination and realistic reflections on PBR materials. You need IBL for interactive product previews, web demos, and cinematic scenes where lighting fidelity and surface reflections heavily impact visual realism.

For real-time scene rendering in Three.js, use AmbientLight for base illumination, DirectionalLight for sun-like rays and shadows, PointLight and SpotLight for localized sources, and RectAreaLight for window-like soft illumination. Combine these with shadow mapping to fit your scene's scale and performance budget.

Yes, PBR materials are required to implement environment lighting effectively in Three.js. Image-Based Lighting (IBL) relies on PBR material properties to calculate accurate ambient illumination and surface reflections, ensuring that environment maps interact realistically with the scene's geometry and light sources.

Performance constraints for Three.js shadows include shadow map resolution limits and the rendering cost of multiple shadow-casting lights. You must balance shadow quality against frame rate by tweaking shadow parameters and limiting the number of active shadow-casting lights in interactive WebGL scenes.