How to Use the Fill Tool in Blender Grease Pencil

Coloring your 2D artwork and animations in Blender is made highly efficient by using the Grease Pencil’s Fill tool. This guide provides a straightforward, step-by-step walkthrough on how to set up your layers, configure your materials, manage line gaps, and successfully apply color fills to your Grease Pencil drawings.

Step 1: Prepare Your Layers

For a clean workflow, it is best practice to keep your outline drawings and your color fills on separate layers.

1. Select your Grease Pencil object and go to the Object Data Properties tab (the green squiggle icon on the right menu).
2. In the Layers panel, click the + icon to create a new layer.
3. Name this layer “Color” or “Fill” and drag it below your “Lines” layer so the color fills do not cover your clean line art.

Step 2: Switch to Draw Mode and Select the Fill Tool

1. Switch from Object Mode to Draw Mode using the mode dropdown menu in the top-left corner of the viewport (or press Ctrl + Tab and select Draw).
2. Select the Fill Tool (the paint bucket icon) from the toolbar on the left side of the screen, or press Shift + F8.

Step 3: Choose or Create a Fill Material

Grease Pencil uses materials to define colors. You must use a material that has the “Fill” option enabled.

1. Go to the Material Properties tab (the red checkered sphere icon).
2. Click the + icon to create a new material slot, then click New.
3. In the material settings, uncheck Stroke and check Fill.
4. Click the color box next to Base Color to choose your desired fill color.

Step 4: Configure the Fill Tool Settings

Before clicking to fill, adjust the tool settings located in the top bar to ensure a clean fill:

• Resolution: Controls the accuracy of the fill. Higher values are more precise but take more processing power.
• Leakage (Gap Closure): If your line art has small gaps, the fill will bleed out. Increase the Leak Size (represented by the padlock/leak icon) to allow Blender to automatically bridge small gaps in your line art.
• Simplify: Simplifies the boundary of the fill shape to reduce the number of vertices.

Step 5: Apply the Fill

1. Ensure your active layer in the Layers panel is set to your “Color” layer.
2. Ensure your active material is set to your Fill material.
3. Click inside the closed area of your line art drawing.

Blender will calculate the boundaries based on your visible strokes and apply the solid color fill. If the fill leaks and colors the entire screen, press Ctrl + Z to undo, increase the Leak Size in the top settings bar, or manually close the gaps in your line art before trying again.