mr Sky

Command entry:Daylight system

Modify panel

Daylight Parameters rollout

Skylight drop-down list

mr Sky

The mr Sky light is intended for use in the mental ray Sun & Sky combination. This topic mainly provides information on parameters unique to this component. A number of mr Sky parameters are common to all three Sun & Sky components. For some of those parameters, this topic provides a brief explanation plus a link to the main topic with additional details.

TipYou can view the Sun & Sky combination in a viewport, which makes adjusting parameters fully interactive. For details, see this procedure.

Interface

mr Sky Parameters rollout

On

Turns the light on and off.

Multiplier

A scalar multiplier for the light output. Default=1.0.

Ground Color

The color of the virtual ground plane. Note that this is a diffuse reflectance value (that is, albedo). The ground appears as a Lambertian reflector with this diffuse color, lit by the sun and sky only, and does not receive any shadows.

TipSome sky models neglect the influence of bounce light from the ground, assuming only the sky is illuminating the scene. To compare the output of mr Sky with, for example, the IES Sky model, set Ground Color to black.

Sky Model

Lets you choose the sky model to use. There are three choices:

Use the Perez or CIE model when you want light from the sky to be physically accurate. These sky models are meant especially for use with lighting analysis in 3ds Max Design: See Lighting Analysis Assistant (3ds Max Design).

mr Sky Advanced Parameters rollout

Horizon group

Height: The vertical position of the horizon. Default=0.0.

For details, see Horizon Height.
Blur: The “blurriness” with which the horizon is rendered. Default=0.1.

At 0.0 the horizon is completely sharp. Generally only values lower than 0.5 are useful, but the full range is up to 10.0 for a horizon that consists of blur only, with no actual horizon at all.

Night Color

Night Color: The minimum color of the sky: the sky will never become darker than this value. This adjustment can be useful for adding things like the moon, stars, high-altitude cirrus clouds that remain lit long after sunset, and so on. As the sun sets and the sky darkens, the contribution from Night Color is unaffected and remains as the base light level.

Non-Physical Tuning group

Red/Blue Tint: Provides artistic control over the redness of the sky light. The default value of 0.0 is the physically correct value (calculated for a 6500K whitepoint), but can be changed with this parameter, which ranges from –1.0 (extremely blue) to 1.0 (extremely red).
Saturation: Provides artistic control over saturation of the sky light. The default value of 1.0 is the physically calculated saturation level. Possible values range from 0.0 (black and white) to 2.0 (extremely high saturation).

Aerial Perspective group

Aerial Perspective toggle: When on, enables the Visibility Distance setting. When off, disables the effect of Visibility Distance. Default=on.
Visibility Distance: Aerial Perspective is a term used by painters to convey how distant objects are perceived as hazier and tinted towards the blue end of the spectrum. mr Sky emulates this with the Visibilty Distance parameter. When nonzero, it defines the “10% distance”, that is, the distance at which approximately 10% of haze is visible at a Haze level of 0.0.

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