## Advanced Lighting Most of the techniques discussed here involve alternatives to using standard lights (or the Sky Light). ### Global Illumination Also referred to as HDRI and Image-Based Lighting. > **Note:** global illumination (indirect, bounced light) and image-based lighting (light from an HDRI) are different things; this heading and line conflate them.  *Brushed steel sphere on parquet plane, with HDRI and Radiosity tags used for lighting. Fast, attractive renders with almost no effort.* > **AI draft:** generated from the Cheetah 3D 8.1.1 manual; not yet reviewed by the author. Using a light probe, light box, or panorama in an **HDRI Light** object to light a scene often produces excellent results with relatively little effort, and also short render times. With the Cheetah renderer you also need to turn on **Radiosity** in its render settings (**Ambient occlusion** is the fast option for HDRI renders); Falcon computes indirect light on its own. > *End of AI draft.* ### Lighting with Emissive Objects You can light scenes entirely using emissive objects and Radiosity. The important thing is to make sure the camera light is off (if set to auto — the default — it will turn on if there are no lights in a scene). The second problem is preventing blotches, which generally involves setting Rmin to be low enough and Samples high enough. > **Note:** needs checking in Cheetah 3D 8.1.1: the manual describes Camera light as a plain on/off property (Objects/SceneObjects/Camera); is there still an “auto” default? Rmin and Samples are now in the Cheetah renderer’s Radiosity settings.