DeslicebetaES

Process › Quality› Wall generatorwall_generator

Wall generator

How the walls are drawn: “Classic” uses lines that are always the same width; “Arachne” narrows or widens them to fill each area.

How it works

Walls are loops that run parallel to the outline of each layer, working inward. The classic generator draws every loop at the same width. Where the shape is thinner than two lines, the second loop doesn't fit: a gap is left that gets patched in little bits with “gap fill”, or the detail simply disappears (small letters, thin ribs).

Arachne measures how much room there is and sets the width of each line on the fly. Where two don't fit, it prints one wider line; where there's a little extra room, it widens them. Nothing disappears and there are no little bits.

The trade-off is that Arachne sometimes splits a wall into sections: two thin lines merge into one wide one and then separate again. Each section is one more seam and a small change in the amount of plastic, and on smooth surfaces that can show. That's why Bambu's profiles come with “Classic”.

When to change it

  • A keychain with raised text, a grille with thin ribs or any part with areas narrower than 0.84 mm (two 0.42 mm lines): Arachne.
  • A box or vase with large, smooth faces and no thin areas, where the finish matters: Classic.
  • If details are missing in the preview with Classic, before switching generators try “Detect thin wall” or a thinner line width.

Typical values

ValueWhat for
ClassicDefault in Bambu Studio; constant widthdefault
ArachneVariable width; saves fine details

Watch out for

  • The six settings below it (threshold angle, filter margin, transition length, distribution count, minimum wall width and minimum feature size) are only used with Arachne.
  • Arachne changes the amount of plastic within a single loop: with filaments that drip or with pressure badly calibrated, the width changes show.
  • With Arachne, slicing takes a bit longer.

Goes well with

Detect thin wallMinimum feature sizeMinimum wall widthWall transitioning threshold angleWall distribution countWall loopsOuter wall
What Bambu Studio saysits help card, quoted

What Bambu Studio says

Classic wall generator produces walls with constant extrusion width and for very thin areas is used gap-fill. Arachne engine produces walls with variable extrusion width

Bambu Studio tooltip for this setting · AGPL-3.0

Read more at the official source

This setting on the Bambu Lab wiki
In your profile0.20mm Standard @BBL A1 · Classic

In Bambu Studio, the profile 0.20mm Standard @BBL A1 sets it toClassic

In other slicers

Orca Slicer
Wall generatorQuality › Wall generator
PrusaSlicer
Perimeter generatorLayers and perimeters › Advanced
Cura
No clear equivalent.

Names taken from each program's code (Orca Slicer 2.4.2, PrusaSlicer 2.9.6, Cura 5.13.0). Credits