How to Create Spirograph Curves in GIMP

This guide explains how to generate intricate mathematical curves and geometric patterns in GIMP using the built-in Spyrogimp plugin. By following these steps, you will learn how to prepare your canvas, locate the Spyrogimp tool, adjust the underlying gear and curve settings, and render precise mathematical patterns directly onto your image layer.

Step 1: Prepare the Canvas and Layer

  1. Open GIMP and create a new project by navigating to File > New. Choose your desired dimensions (a square canvas such as 1080x1080 pixels works best for symmetrical patterns).
  2. Go to the Layers panel and click Create a new layer. Name this layer "Spirograph" and set the Fill with option to Transparency. Working on a transparent layer allows you to manipulate, colorize, or move the curve independently from the background.

Step 2: Set Brush and Foreground Color

Spyrogimp uses your active brush settings or solid lines depending on the render mode chosen.

  1. Select the Foreground Color from the toolbox and choose the color you want for your curve.
  2. Select the Paintbrush Tool (P) and pick a simple brush, such as "2. Hardness 100", adjusting the size to 1–3 pixels for clean, distinct lines.

Step 3: Launch Spyrogimp

  1. Ensure the transparent layer created in Step 1 is selected.
  2. Go to the top menu and select Filters > Render > Spyrogimp....
  3. A dialog window will appear alongside an interactive preview directly on your canvas.

Step 4: Configure the Mathematical Parameters

Spyrogimp provides several tabs to customize the mathematical equations governing the curve:

  • Curve Type: In the Curve Type tab, select between Epitrochoid (external gear movement, producing star-like or floral shapes) or Hypotrochoid (internal gear movement, producing classic Spirograph loops).
  • Shape: Choose the fixed gear shape, such as a circle, frame, polygon, or heart.
  • Gears Tab:
    • Outer/Fixed Teeth: Sets the number of teeth on the fixed ring.
    • Inner/Moving Teeth: Sets the number of teeth on the rotating gear. The ratio between these two values determines the number of petals or loops the pattern forms.
    • Pen Margin/Position: Determines the distance of the drawing point from the center of the moving gear, controlling the depth and sharpness of the loops.
  • Rotation and Margin: Adjust the margin to scale the curve within the canvas and set the angle of rotation to position the design.

Step 5: Render the Design

  1. Under the Render tab, choose your drawing method. You can render the curve as a continuous line, a gradient stroke, or using the current active brush.
  2. Review the on-canvas preview to confirm the design matches your requirements.
  3. Click OK in the Spyrogimp dialog to calculate the mathematical path and commit the stroke to your layer.