Shells

Also known as: Perimeters, Walls, Wall Count, Wall Line Count

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The outer vertical surfaces of a print that form the visible exterior.

Shells (also called perimeters or walls) are the outer vertical surfaces of your print. They form the visible exterior and contribute significantly to strength.

How Many Walls?

  • 2 walls - Minimum, light prints
  • 3 walls - Standard, good balance
  • 4+ walls - Strong, functional parts

Walls vs. Infill for Strength

More walls often provide more strength than more infill:

  • 3 walls + 20% infill is often stronger than
  • 2 walls + 50% infill

Line Width Considerations

Wall line width affects appearance:

  • Standard (0.4mm) - Matches nozzle
  • Slightly wider - Better adhesion
  • Thinner outer - Finer details

Types of Walls

  • Outer wall - Visible surface, print slower
  • Inner walls - Can print faster
  • Thin walls - When model is too thin for multiple walls

Tips

  • Use odd number of walls to end on inner wall
  • Outer wall speed affects surface quality
  • Wall overlap percentage affects adhesion to infill
  • Print outer walls first for dimensional accuracy