Information about the Sun/Sky

[joe_b]

The following is an excerpt from Chaos: Industry-leading design and visualization software - Though this explains the VRaySun/Sky in 3dsmax, the params are the same.

@Spot3d Sun/Sky Params

Turbidity - this parameter determines the amount of dust in the air and affects the color of the sun and sky. Smaller values produce a clear and blue sky and sun as you get in the country, while larger values make them yellow and orange as, for example, in a big city. For further info, please see the Examples section.

Ozone - this parameter affects the color of the sun light. Available in the range between 0.0 and 1.0. Smaller values make the sunlight more yellow, larger values make it blue. For further info, please see the Examples section.

Intensity multiplier - this is an intensity multiplier for the VRaySun. Since the sun is very bright by default, you can use this parameter to reduce its effect. See the Notes and Examples sections for more information.

Size multiplier - this parameter controls the visible size of the sun. This affects the appearance of the sun disc as seen by the camera and reflections, as well as the blurriness of the sun shadows. For further information, please see the Examples section.

Shadow subdivs - this controls the number of samples for the area shadow of the sun. More subdivs produce area shadows with better quality but render slower. For further info, please see the Examples section.

Shadow bias - moves the shadow toward or away from the shadow-casting object (or objects). If the bias value is too low, shadows can “leak” through places they shouldn’t, produce moire patterns or making out-of-place dark areas on meshes. If bias is too high, shadows can “detach” from an object. If the bias value is too extreme in either direction, shadows might not be rendered at all. For further info, please see the Examples section.

Photon emit radius - determines the radius of the area, in where photons would be shot. This area is represented by the green cyllinder around the Sun’s ray vector. This parameter has effect when photons are used in the GI solutions or caustics.