// What it does
Sets which axis the slicer will treat as 'up' (the build-plate normal). Affects the build-plate plane gizmo, all swap-bar / flush-waste calculations, and the Z written into the exported 3MF.
Controls: Up axis (X / Y / Z, default Z), Flip up/down, and an auto-suggester that fires when a different up-axis would cut flush waste by ≥30%.
// When to use it
- Right before export, after painting is done.
- When the slicer needs the model laid on a specific face for the print to work mechanically (overhangs, support strategy).
- When the auto-suggester fires — it's usually right.
// How to use it
- Export tab → Build orientation. Confirm Up axis is Z (slicer default).
- Open Check tab → Show swap bar so the suggester has data to work with.
- Try flipping the Up axis to compare swap counts in the status line.
- Auto-suggester banner appears if a better axis exists. Click Apply or Dismiss.
// Tips
- Confusing with Orient model? Orient model rotates the mesh; Build orientation tells the slicer which way is up. Different jobs.
- Don't ignore the suggester — a 30%+ flush-waste cut is grams of filament saved per print.
- Suggester silent? Show swap bar must be on — it depends on the swap data.