Stroke Bezier Curves with Paint Dynamics in GIMP

Stroking a complex Bezier curve with dynamic paint tools allows you to achieve natural, expressive line art with tapered ends and variable line weight, even without a graphics tablet. This guide demonstrates how to create a vector path, configure GIMP's paint dynamics to simulate pen pressure variations, and render the stroke cleanly along your curve.

Step 1: Draw the Bezier Curve

  1. Select the Paths Tool from the toolbox or press the shortcut key B.
  2. Click on your canvas to place anchor points, clicking and dragging to extend the Bezier handles to form smooth, complex curves.
  3. Hold Ctrl and click the initial node if you need a closed loop, or leave it open for an open stroke.

Step 2: Configure the Brush and Tool Options

  1. Select the Paintbrush Tool (P).
  2. Choose your desired brush tip from the Brushes dialog (a standard round brush like "2. Hardness 050" works well for clean line work).
  3. Set the base Size of your brush in the Tool Options panel; this will act as the maximum width of your stroke.

Step 3: Set Up Variable Pressure Simulation

Because Bezier paths lack physical stylus pressure data, you must map pressure simulation through GIMP’s Paint Dynamics engine:

  1. In the Paintbrush Tool Options, expand the Dynamics section.
  2. If you want a tapered stroke that thins at the ends, select a preset like Pressure Opacity or Fade Tapering.
  3. To customize the behavior, open the Paint Dynamics Editor via Windows > Dockable Dialogs > Paint Dynamics. Create a new dynamic and map Fade or Velocity to Size.
  4. Under the Paintbrush Tool Options, expand Dynamics Options and adjust the Fade length. This distance determines how long the brush takes to transition between minimum and maximum width along the path.

Step 4: Stroke the Path

  1. Open the Paths Dialog (Windows > Dockable Dialogs > Paths).
  2. Right-click your active path and select Stroke Path, or navigate to Edit > Stroke Path from the top menu.
  3. In the Stroke Path dialog, select Stroke with a paint tool.
  4. Choose Paintbrush from the dropdown menu.
  5. Check the box labeled Emulate brush dynamics. This setting forces the stroke engine to read the dynamics and fade settings you defined, simulating pressure changes along the Bezier curve.
  6. Click Stroke.

Step 5: Fine-Tuning Results

If the line does not taper as desired, press Ctrl + Z to undo the stroke. Increase or decrease the Fade length in the Paintbrush Tool Options to match the scale of your curve, adjust the base brush size, and run the Stroke Path command again.