Inject an EditorEnvironment wrapper (drei prefiltered sunset HDRI at environmentIntensity 0.6) as a child of the editor Viewer, not baked into the Viewer component, so read-only/embed viewers stay lightweight. This gives PBR metals their reflections and lifts lighting on vertical walls that flat directional + hemisphere lights cannot. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>