Name

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

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.

Zenith

The base color of the sky directly overhead

Horizon

The color of the sky at the horizon

Limit

The angle, in degrees, below which the sky isn’t mapped. The angle is measured positively from the horizon toward the zenith, in degrees. This parameter may be used to reduce any aliasing that might arise on 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.

Diffusion

The amount of diffusion of the sky colors into the texture-mapped zone of the ceiling. This parameter in conjunction with the limit value can be used to simulate atmospheric haze.

X, Y Scaling

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

X, Y Rotation

Rotates the X and Y direction of the sky component.

X, Y Translate

Here Width and Depth control the offset of the sky in the X and Z directions, respectively.

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 make 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

There is no texture displayed in the angular sector that this value defines. The angle is measured positive from the horizon towards 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.