Glossary

Sky and cloud rendering terminology used across the docs.

Atmosphere

Azimuth

Horizontal angle of the sun, measured around the horizon. Together with elevation it fully specifies sun direction.

Elevation

Vertical angle of the sun above the horizon. 0° is sunset/sunrise; 90° is directly overhead.

Turbidity

Aerosol concentration in the atmosphere. Higher values produce more haze and lower color saturation. Controlled by atmosphere.turbidity.

Mie Scattering

Scattering caused by aerosols and similarly sized particles. It produces the bright halo around the sun. Control it with atmosphere.turbidity, atmosphere.mieDirectionalG, and atmosphere.mieScatteringStrength.

Rayleigh Scattering

Light scattering by molecules much smaller than the wavelength of light. Short wavelengths (blue) scatter more, producing blue skies and red sunsets.

Sun Disc

The visible disc of the sun rendered onto the sky dome. Size and brightness controlled by sun.discSize and sun.intensity.

Exposure

Brightness scale applied before bloom and tone mapping. Controlled by atmosphere.exposure.

Clouds

Coverage

Fraction of available cloud coverage, from 0 to 1. Higher values produce a more overcast sky.

Density

Optical density of the cloud medium. Higher values produce darker, more opaque clouds.

Weather Map

2D texture controlling regional cloud coverage. The density field reads coverage from the red channel.

Detail Erosion

High-frequency noise that erodes the silhouette of cloud bodies, creating wispy edges.

Multiple Scattering

Approximation of light scattering through a cloud more than once before exiting. It brightens dense cloud interiors and undersides.

March Steps

Maximum number of raymarch samples taken along a primary view ray when integrating cloud density. Fixed at 256 for every quality tier — the tier controls reconstruction resolution while cloud rendering mode controls how many rays render per frame.

Staggered Cloud Rendering

Rendering part of the fresh cloud data each frame and filling the remaining pixels with recent history. Static and Dynamic modes refresh every sample over 16 frames. Ultra Dynamic refreshes every sample over 4 frames, which responds faster but renders four times as many cloud rays per frame.

Temporal Reconstruction

Combining the current frame's raymarched cloud samples with reprojected samples from recent frames. The reconstruction target is 1/4 width and height on Low and 1/2 width and height on Medium, High, and Ultra.

Light Steps

Number of raymarch samples toward the sun at each primary sample, used to compute in-scattering. Fixed at 6 for every quality tier.

God Rays (Crepuscular Rays)

Volumetric light shafts radiating from the active light (sun by day, moon at night). They respect scene depth and lean with the light's elevation. Controlled by sky.godRays.