How to Use Fill Brush to Patch Holes in Blender

The Fill brush in Blender's Sculpt Mode is an essential tool for leveling out deep cavities, smoothing unwanted dips, and patching surface gaps on 3D models. By building up depressed areas until they match the height of surrounding vertices, it allows artists to quickly repair geometry without distorting adjacent mesh details. This guide covers how to set up your mesh, configure brush settings, and effectively use the Fill brush alongside dynamic resolution tools to close holes seamlessly.

Step 1: Enable Dyntopo or Remesh the Model

The Fill brush operates by pulling existing geometry upward. If your model has an open mesh hole with completely missing faces, you must generate new geometry while painting.

  1. Switch to Sculpt Mode using the top-left menu.
  2. In the top bar, enable Dyntopo (Dynamic Topology) or press Ctrl + D.
  3. Set the Detailing option to Relative Detail or Constant Detail. This ensures new vertices are automatically created over empty spaces as you paint.

Alternative: If working with closed but thin gaps, you can use the Voxel Remesher (Ctrl + R) to close the gap before using the brush.

Step 2: Select and Set Up the Fill Brush

  1. Select the Fill brush from the toolbar on the left.
  2. Press F to adjust the brush radius to cover the area comfortably.
  3. Press Shift + F to adjust brush strength. A moderate strength setting between 0.3 and 0.6 offers the best control.

Step 3: Fill the Cavity

  1. Hover the cursor along the border of the hole or depression.
  2. Click and hold while dragging the brush across the gap. The brush calculates the average height of the surrounding edges and builds the mesh up to match that plane.
  3. Paint in overlapping strokes until the empty area is filled flush with the rest of the model.

Step 4: Smooth and Blend the Surface

Once the gap is filled, the surface may look uneven or jagged due to newly generated topology.

  1. Hold Shift while brushing over the repaired area to temporarily activate the Smooth brush.
  2. Gently stroke the surface to blend the filled patch into the surrounding geometry smoothly.
  3. Release Shift to return to the Fill brush if additional leveling is required.