Cloud

Category: Texture Generators

Shader Family: Texture

Output: Color

Creates a cloud-like texture based on a coordinate input. It is based on a 3D fractal function, which can be animated.

Name	The shader's name. Enter any name you like, or leave the default.
Noise Type	You can select two noise functions to build the fractal: Type 0 is a Perlin-type noise Function, and type 1 is a recursive function with slightly different characteristics.
Absolute	Makes the shader animate the fractal in time. Animating the value of the Time parameter also does this. If you make it change between frames, the fractal texture will change in a continuous manner between these frames.
Complexity	The maximum number of noise iterations used when calculating the fractal. It works in conjunction with Level Minimum in determining the complexity of the fractal.
Level Minimum	The minimum amplitude at which iteration will continue. Used to determine how often the noise function is called. You can use this parameter to control the amount of detail in the texture.
Level Decay	The amplitude of decay of the fractal iterations. It is defined as the ratio of the amplitudes of two successive iterations. For values less than 1, the amplitude of successive iterations decreases; for values greater than 1, the amplitude of successive iterations increases and the fractal becomes unbounded.
Frequency Multiplier	The frequency multiplier for subsequent iterations. Fractal frequency is the inverse of scale. Doubling this frequency with this parameter is the same as scaling down the texture by a factor of 0.5. This means that a value of 1 will give a sharp fractal texture with low detail, while a value of 2 gives a more detailed and varying texture.
Time	Defines time (in seconds) used to animate clouds.
Coordinates	Defines the U, V, and Z texture coordinates of the texture.
Color 1	Defines the color of fractal clouds.
Color 2	Defines the color used for the sky (constant background color).
Include Alpha	Calculates the alpha channel when rendering.
Contrast	Controls the contrast of the colors. For a value of 0, the average of the two colors is used, and no blending is attempted. This speeds up rendering somewhat.
Edge Transparency	Switches on the edge transparency parameters.
Transparency Range	Controls the abruptness of the change from the center of the cloud to its edge. If the value is small, the change is abrupt.
Amplitude	Defines the base amplitude of the fractal used to calculate the edge transparency. This parameter only applies to the amplitude of the first iteration; successive iterations may further increase the amplitude.
Center Threshold	Defines the average alpha value at the center of the cloud.
Edge Threshold	The corresponding value for the cloud's edge (see the above parameter).

Render Tree Usage

Use this shader to drive a parameter with a texture effect anywhere in a render tree. This shader generates a texture that can be used as a color, a weight value in a mixer shader, or to drive any Surface shader parameter.

The Coordinates parameter can be driven by (connected to) the texture_space_generator tool shader.