The environment declared the sky as its ambient source without a sky, so shadowed faces received no ambient light. A procedural underwater sky now feeds ambient and reflections; the directional light is steeper and stronger with 70 % soft shadows; SSAO, filmic tonemapping, aerial perspective and tinted volumetric fog complete the pass. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>