HDRI
High Dynamic Range Image lighting
Also known as: Image-Based Lighting · IBL · Environment map
Definition
An HDRI (High Dynamic Range Image) is a 360-degree photographic capture of a real environment with full lighting information, used to light 3D scenes via image-based lighting (IBL). HDRIs deliver realistic ambient lighting and accurate reflections in a single asset — open-sky HDRIs make outdoor scenes look correct without manually placing light sources.
In production
Marmoset Toolbag ships with a strong HDRI library specifically curated for portfolio renders, including studio-lit sets and outdoor skies at 8K-16K resolution that make baked normal and AO maps read clearly for turntable presentations. Unreal Engine 5 supports HDRIs through its Sky Light and Sky Atmosphere systems for environment lighting, typically capturing the Sky Light's cubemap at runtime rather than importing a static HDRI file for real-time scenes. HDRIs are captured on location with a 360-degree camera rig or a fisheye lens and a chrome/gray sphere pair, then stitched and stored in an HDR format like .hdr or .exr that preserves the extreme brightness range from a light bulb to direct sun in a single file — a standard 8-bit JPEG can't hold that range without clipping. A common mistake is using a low-resolution or poorly exposed HDRI as the sole reflection source, which produces blurry or blown-out reflections on glossy metal materials.