TouchDesigner Tutorial: Working with the Noise TOP

This tutorial covers the Noise TOP in TouchDesigner, a powerful tool for generating organic shapes from clouds to cellular patterns.

Noise Types and GPU Acceleration

The Noise TOP offers various noise algorithms through the Type parameter:

• Simplex 3D GPU (default)
• Perlin 3D GPU
• Random noise
• Alligator noise

Important: Noise types with “GPU” in parentheses are GPU-accelerated and more performant. Keep this in mind when choosing which noise to work with for optimal performance.

Key Parameters

Seed

The seed parameter generates different noise patterns based on the number value. The noise is deterministic - the same seed value always produces the same pattern. This is useful when you need reproducible results.

Period

The period parameter controls the zoom level of the noise by adjusting the separation between peaks:

• Larger period = more stretched out, zoomed-in noise
• Smaller period = more detailed, zoomed-out noise

Amplitude

Controls the scale of the noise output. Setting amplitude to 0 reveals the base offset value.

Offset

Refers to the midpoint source of the noise (default: 0.5 gray value). This value is added to every pixel in the noise output.

Monochrome

• On (default): Grayscale noise
• Off: Colorful noise with RGB variation

Animating Noise

To create flowing movement, navigate to the Transform page and use the Translate TZ parameter with an expression:

absTime.seconds * 0.5

Adjust the multiplier (0.5) to control animation speed - lower values create slower movement.

Creating Large Color Washes

For big gradient washes of color:

1. Turn off Monochrome
2. Increase the Period value significantly
3. The result: large, flowing color gradients perfect for backgrounds

Working with Inputs

The Noise TOP has two inputs:

Input 1: Background Image

• Sets the resolution of the noise
• Can be combined with the noise output
• Example: Connect a Ramp TOP to control both resolution and color

Input 2: Noise Coordinate Map

• Provides additional control for shaping noise output
• Uses coordinate values to inform how noise is computed

Coordinate Map Examples

Horizontal Gradient (Ramp)

When using a horizontal ramp as a coordinate map:

• Noise coordinates only change left to right
• Each vertical line of pixels shares the same noise value
• Result: Vertical bands of noise

Vertical Gradient

Using a vertical ramp creates horizontal lines of noise.

Combined Coordinate Map

Use a Reorder TOP to combine horizontal and vertical ramps:

1. Connect Ramp 1 (horizontal) to first input
2. Connect Ramp 2 (vertical) to second input
3. Set Output Green to use the second input
4. Result: A combined coordinate map with both directions

Output Options

On the Output page, the RGB parameter controls how inputs combine:

• Input plus noise: Adds background image and noise together
• Noise only: Uses background image only for resolution

Switching Between Coordinate Maps

Use a Switch TOP to toggle between different coordinate maps:

1. Connect multiple coordinate maps (ramps, reorder output)
2. Adjust the Index parameter to switch between them
3. Useful for comparing different noise patterns

Practical Tips

• Use the middle mouse button with the value ladder for precise parameter adjustments
• Set Viewer Smoothness to “Nearest Pixel” on the Common page for clearer viewing of low-resolution noise
• The Phase parameter on Ramp TOPs can be animated to create additional movement in coordinate-mapped noise