Build a Chase Effect

Build a chase effect that moves across your fixtures.

Goal

Create a rainbow chase effect that:

• Cycles through colors
• Moves across fixtures in sequence
• Responds to BPM

Time: 15-20 minutes

Prerequisites

• A project with at least 4 fixtures patched
• Basic familiarity with the Node Editor

Step 1: Set up your canvas

1. Open the Node Editor panel
2. If there are existing nodes, clear them or create a new layer
3. Right-click the canvas to open the node menu

Step 2: Add a Time node

The Time node provides a continuously increasing value based on BPM.

1. Add Input > Time node

Step 3: Create the chase pattern

Use Pixel Position to offset the animation per fixture:

1. Add Input > Pixel Position node
2. Add Arithmetic > Add node
3. Connect Time output to first input of Add
4. Connect Pixel Position to second input of Add

This creates an offset pattern: each fixture sits at a different point in the animation.

Step 4: Create the color

Convert the animated value to a color:

1. Add Rounding > Fractional Part node (keeps only the decimal part)
2. Connect Add output to Fractional Part input
3. Add Color > HSL to RGB node
4. Connect Fractional Part output to Hue input
5. Set Saturation to 1.0 and Lightness to 0.5

Step 5: Output the color

1. Add Color > Combine Color node
2. Connect HSL to RGB Red, Green, Blue outputs to the corresponding Combine Color inputs
3. Add Output > Output node
4. Connect Combine Color output to Output

Step 6: Test the effect

1. Start playback from the toolbar
2. Watch the Preview panel; colors should chase across the fixtures
3. Adjust the layer's Speed Multiplier in the Layer Settings panel to change chase speed

Step 7: Fine-tune

Adjust chase width

To make the chase smoother:

1. Add Arithmetic > Multiply after Add
2. Multiply by 0.25 to make each fixture span 1/4 of the color wheel
3. This creates a wider, smoother gradient

Add dimming

To fade fixtures in and out:

1. Add Wave > Sine node
2. Connect the Fractional Part output to its input
3. Use the sine output as the Lightness in HSL to RGB

Final node graph

Your completed graph should look like:

Time ────────┐
             ├──► Add ──► Multiply ──► Fractional Part ──► HSL to RGB ──► Combine Color ──► Output
Pixel Pos. ──┘                              │
                                            └──► Sine ──► (Lightness input)

Experimentation

Try these variations:

• Change the color range by offsetting the Hue
• Use different wave shapes for dimming
• Add a Threshold node for hard cuts instead of fades

Next steps

• Add beat synchronization
• Learn more node types
• Build a complete show