Fractal Scalar

Color | Noise | Texture Support | Render Tree Usage

Category: Texture

Shader Family: Texture

Output: Scalar

The Fractal Scalar shader, based on Perlin noise, adds noise to a particle volume to help define its density's shape. This is especially useful for creating certain volumic effects, such as smoke and clouds. You can also animate the fractal pattern of the noise.

You usually use the Fractal Scalar shader in conjunction with the Particle Density and Particle Volume Cloud shaders. The fractal pattern is added to the shape of each particle, with the effect usually most visible at their edges.

Using this shader, you may need to emit fewer particles to create an effect because you can create a certain level of detail and complexity using the shader itself. For example, instead of adding thousands of particles for creating a billowing smoke effect, you can use fewer and larger particles, then add the smoke detail with the fractal noise from this shader.

For general information about ICE particle shaders, see ICE Particle Shading.

TipTo save time previewing the results of the fractal pattern, click the little V above the Fractal Scalar shader's node in the render tree to display its shaderball view. This way, you can turn off the render region to save time while tweaking only the fractal pattern.

Color

Color 1, Color 2

Sets the minimum and maximum contrast values for the noise pattern.

For example, if you set Color 1 to 0 and Color 2 to 1, there will be a full black/white contrast in the noise pattern.

Invert Colors

Switches the values of Color 1 for Color 2, and vice versa.

Contrast

Clamp Min/Max	Clamps the Color 1 and 2 minimum and maximum values to change the contrast of the pattern.
Bias (Gamma)	Overall amount of white and black used for the contrast.

Noise

Type of Noise

Noise Type

Use either of these noise calculations:

Fractalsum - Noise gets repeated at smaller scales with smaller amplitudes for getting a fine level of detail.
Turbulence - Noise with areas of more pronounced contrast. White areas of the pattern render as volume (peaks), while black areas render as cracks or fissures (valleys).

Fractalsum	Turbulence

Recursion

Level

Number of iterations of the noise function you've selected (Fractalsum or Turbulence). The higher this value, the more finely detailed the noise pattern. See example images below for value usage.

Next Recursion Level

Scale down: Reduces the scale for the noise for the next recursion level. See example images below for value usage.
Gain/Smooth: Reduces the intensity for the recursion levels. With a value of 1, each recursion level gets the same amount of intensity, which leads to a small high contrast noise. With a value of 2, each level gets half of the previous layer, so the pattern gets softer in the small details. See example images below for value usage.

Recursion Level

1	2	3	4	5

Scaledown

1.5	2.0	3.0	4.0	5.0

Gain/Smooth

0.5	1.0	2.0	3.0	5.0

Distortion

Distort

Distorts the noise with a Perlin noise, making for more psychaedelic effects! See example images below for value usage.

Note that distortion can increase the render time by up to 5 times!

Distort Scale

Scale of the distortion pattern. Higher values create a more finely detailed pattern.

Distort

0	20	40	60	100

Distort Scale

2	3	4	5	10

Time

Changes the fractal pattern over time.

No change over time: The fractal pattern doesn't change. If you select this option, the additional 4th dimension of time for the noise is not calculated, which means less render time.
Constant: The animation is done in a linear fashion. You can set the Speed value, but not the Time value; that is, you cannot animate this value.
User Animated: You can animate the Time value to make the fractal pattern change as you like.

Speed

Determines how quickly the fractal pattern changes. This is the rate without any acceleration. You can set this only if you select Constant.

Time

Set keys on this parameter to animate the time, which changes the acceleration of the fractal pattern. You can set this only if you select User Animated.

Texture Support

Coordinates

Input for Texture Coordinates

Select your texture space in XYZ.

External Coordinates or Auto Spatial (if no input)

If this option is on, the shader uses the input shader's texture coordinates.

If no input shader is used, basic object texture coordinates are automatically created.

Coordinate Scale

Pre-Scale	Sets the general scale of the texture coordinates: Big Noise, Default, Small Noise.
Scale	Once you have set the Pre-Scale size, you can fine-tune the scale of the texture coordinates. This slider scales the texture coordinates uniformly on all axes.
Scale per Axis	Sets the scale separately on each XYZ axis.

Render Tree Usage

Plug this shader into the density_shape and/or density_texture ports of the Particle Density shader, which is plugged into the density port of the Particle Volume Cloud shader.

For more realistic or complicated smoke effects, you may want to use two Fractal Scalar shaders, one for each density port, or add a Cell Scalar shader to create fractals on a larger scale.