Change weather and lighting¶

BBI allows you to vary environmental parameters including weather and lighting. These are accessible through world.env.weather and world.env.time_of_day.

Manual weather control¶

Weather attributes can be set directly using the following methods:

Example: changing weather parameters and time of day¶

world.env.weather.set_cloud_coverage(5)
world.env.weather.set_fog_distance(100)
world.env.weather.set_fog_intensity(3)
world.env.weather.set_fog_max_opacity(0.5)
world.env.weather.set_rain_intensity(5)
world.env.weather.set_rain_screen_droplets(ScreenDropletsPreset.MEDIUM)
world.env.weather.set_sky_atmosphere_contribution_color_scale(Color(1.0, 0.5, 0.5, 1.0))

Cloud coverage¶

float

Cloud coverage controls the amount of cloud cover in the sky. Recommended values range from 0.0 (no clouds) to 10.0 (completely overcast). Values more than 10 work, but are not generally useful.

Fog distance¶

float

Fog distance controls the distance at which fog starts to appear. The value is in meters.

Fog intensity¶

float

Fog intensity controls the density of the fog. Recommended values range from 0.0 (no fog) to 10.0 (dense fog). For foggy scenes, a value of 3.5-6.0 is recommended. Tweaking the fog intensity alongside the fog distance is recommended. Values more than 10 work, but are not generally useful.

Fog max opacity¶

float

Fog max opacity controls the maximum opacity of the fog. Values range from 0.0 (transparent) to 1.0 (opaque).

Rain intensity¶

float

Rain intensity controls the amount of rain. Recommended values range from 0.0 (no rain) to 10.0 (heavy rain). A value of 5.0 is recommended for moderate to heavy rain.

Rain screen droplets¶

ScreenDropletsPreset

Rain screen droplets control the visibility of rain droplets on the screen. This is useful for simulating raindrops on the camera lens. Values are either NONE, LIGHT, MEDIUM or HEAVY.

`bbi.ScreenDropletsPreset.NONE`	No droplets on the camera lens
`bbi.ScreenDropletsPreset.LIGHT`	Small droplets on the camera lens
`bbi.ScreenDropletsPreset.MEDIUM`	Small running droplets on the camera lens
`bbi.ScreenDropletsPreset.HEAVY`	Large running droplets on the camera lens

Fog sky atmosphere contribution color scale¶

Color

Fog sky atmosphere contribution color scale controls the color of the fog. The color is specified using a Color object. Color values range from 0.0 to 1.0 for each channel (red, green, blue, alpha).

Manual lighting control¶

Note

Use either manual sun parameter control or time of day to change the weather. Using both may result in unexpected behavior.

Lighting can be set directly using the following methods:

Example: simulate sunset by changing sun parameters¶

world.env.weather.set_sun_azimuth(180)
world.env.weather.set_sun_elevation(5)
world.env.weather.set_sun_intensity(10)

Weather presets can be used to quickly set a combination of weather parameters.

Example: simulate sunset by setting time to 18:00¶

world.env.time_of_day.set_time(18)

Sun azimuth¶

float

Sun azimuth controls the position of the sun. Values range from 0 (north of the default camera), to 90 (east), 180 (south), 270 (west), up to 360 (same as 0). Negative values work as well.

Sun elevation¶

float

Sun elevation controls the vertical position of the sun. Values range from 0 to 90 degrees, with 0 being at the horizon, and 90 being directly overhead. Negative values do not work. Values above 90 work, but are not generally useful as they become conflated with the sun azimuth control.

Sun intensity¶

float

Sun intensity controls the brightness of the sun. Recommended values range from 0.0 (no sun) to 50.0 (very bright sun). Values above 50 work but may be too bright.

Time¶

int

Time controls the hour of the of day. Values range from 0 to 24, with 0 being midnight and 12 being noon. When using world.env.time_of_day.set_time(), avoid using the world.env.weather.set_sun_*() methods.

Animating weather and lighting¶

Weather and lighting can be animated through scenario keyframes, allowing them to vary across frames.

Example: animating weather and lighting¶

scenario = world.new_scenario(num_frames=10)

for i in range(scenario.num_frames):
    scenario.set_keyframe(world.env.weather, i, sun_azimuth=180 - i * 10, sun_elevation=5 + i * 2)

    if i % 2 == 0: # Toggle rain every other frame
        scenario.set_keyframe(world.env.weather, i, rain_intensity=5)
    else:
        scenario.set_keyframe(world.env.weather, i, rain_intensity=0)