← All tutorials // 28 Fix & refine

Fill borders.

Two regions, two clean colours, but at the seam — grey slivers. Run Fill borders → slivers get absorbed into the dominant neighbour colour. Clean seam.

// What it does

Walks every triangle on a colour boundary and re-assigns it to whichever colour dominates its immediate face neighbours. Repeats for Fill steps iterations (default 3) so it can crawl multi-tri-deep slivers.

// When to use it
  • After painting two adjacent regions different colours, when zooming in shows grey/wrong-colour slivers between them.
  • Before export, as a general 'tidy the seams' pass.
  • After Region work where a fill stopped one tri short of a clean boundary.
// How to use it
  1. Check tab → Fill borders (Fill steps = 3 by default).
  2. Click the button. Slivers get absorbed.
  3. Zoom in to verify the seam is clean.
  4. Ctrl+Z if it ate something it shouldn't have.
// Tips
  • Steps too high? Steps = 3 is fine for most slivers. Steps = 10 will crawl deep into your painted area and replace things you didn't want replaced. Start low.
  • Running it before painting does nothing — needs adjacent painted areas.
  • Right-click → Fill borders (whole mesh) runs the same action without switching tabs.

Try fill borders on the demo robot.

Open the painter and have a play.

Open the painter →