Time of Day & Atmosphere

The execution model is in blender-core. Studio and product lighting are in blender-lighting-lookdev, render settings in blender-rendering, and rain, snow, wetness and lightning in blender-weather-fx.

One call

scripts/scene_mood.py -- --time golden                       # sun 6 deg, warm, long shadows
scripts/scene_mood.py -- --time night --fog-visibility 250   # moonlight + stars + haze
scripts/scene_mood.py -- --time noon --overcast 0.8          # soft grey day
scripts/scene_mood.py -- --mood cyberpunk                    # moonless, neon rim pair, fog, bloom
scripts/scene_mood.py -- --time morning --fog-visibility 120 --fog-height 4   # valley fog

Times: noon morning afternoon golden sunrise sunset blue_hour night moonless. Moods: cyberpunk horror underwater desert (each sets defaults that explicit flags override). Override the sun with --elevation DEG (negative = below the horizon) and --heading DEG (0 = +Y, 90 = +X). If you leave out --heading, the sun sits 135° from the camera's view direction, which gives side/back light that shows form. Front light looks flat.

The script builds ENV_World, the ENV_Mood collection (sun or moon, fog box, accent lights) and, for moods, ENV_Grade (a compositor tree). Your objects are untouched, and re-running replaces everything it made. It returns the key light's strength, color and elevation, the exposure, and any warnings.