Name

The shader’s name. Enter any name you like, or leave the default.

Zenith

The base color of the sky directly overhead

Horizon

The color of the sky at the horizon

Horizon/Zenith Bias

The bias between Horizon and Zenith color. A value > 0.5 results in the sky color being more inclined to the Zenith color than the Horizon color, and vice versa.

Y Rotation

The rotation of the sky around the center of the zenith

Density

Defines how much of the sky is occupied with stars.

Bias

A bias on the random brightness distribution

Brightness

Scales the brightness of the stars. Sometimes they are too faint and have to be scaled to become visible.

Saturation

The color saturation of the stars. They have random colors that can be made visible by increasing the saturation.

Variation

Controls how much the brightness varies with time.

Twinkle

The time with which the star’s brightness varies

X, Y Scaling

A scaling factor for the stars

Rotation

Rotates the stars about the azimuth.

X, Y Translation

An offset factor for the stars

No Ground/Sky Mirror

Makes the ground a mirror image of the ceiling.

RGB Intensity

Uses the intensity of the color in the texture file to determine the blend.

Alpha Channel

Uses the alpha channel of the texture file to determine the blend.

None

No blending. The texture dominates.

Real Ground

Causes the texture to do some additional calculations for the ground to allow it to be at a finite distance. In fact, the ground is placed at the Y position 0. This allows objects to change appearance as they move along the ground. Also, the effect of Ground Limit and Ground Diffuse change, and only the Ground Horizon color is used as a background color to the texture. Otherwise, both the sky and the ground are infinitely far away in all directions so that translations have no effect.

Base Color

Defines the color of the ground center, directly below you or the camera.

Horizon Color

Defines the color of the ground nearest to the horizon.

Horizon/Base Bias

The bias between the Base Color and the Horizon Color.

Limit

Displays displayed in the angular sector that this value defines. The angle is measured positively from the horizon toward the base, in degrees. When “Real Ground” is selected, however, this limit is not in degrees but in units of “distance.” This is a product of the distance to the point on the texture and how obliquely the ray strikes the texture. So, if the texture is either far away, or viewed at an oblique angle, or both, it is “distant.” In this case, try values of 500-1000 to start with.

Diffusion

Increasing this value blends the area outside the Ground Limit into the ground texture, producing a smooth transition between them. Essentially, the base ground color is allowed to exponentially diffuse into the texture. This gives the texture a hazy appearance as it approaches the horizon. When “Real Ground” is on, the effect is slightly different. Then this value specifies the number of units of “distance” over which the Ground Horizon color blends into the ground texture.

X, Y Scaling

Width and Depth determine the scaling of the Ground Texture in the X and Z directions, respectively. High values stretch the texture while lower ones make the texture repeat more often.

X, Y Rotation

Rotates the X and Y direction.

X, Y Translate

Here Width and Depth control the offset in the Ground Texture in the X and Z directions, respectively.