How is ambient light used to fill in shadows in 3D renders?

Ambient light fills shadows in 3D renders by adding uniform, non-directional illumination to soften shadow edges and reduce their depth, balancing the scene’s overall lighting. As a diffused, directionless source, it brightens shadow areas that might otherwise appear overly dark or flat, avoiding new shadows unlike directional lights (e.g., sun, spotlights). Adjust its intensity to refine: lower values preserve shadow depth for drama, while higher values create a softer, more evenly lit scene. This ensures shadows stay natural yet balanced, enhancing render realism.