Move the cutting head around the bed. Buttons jump to each corner by position; the live path length in the HUD tells you which is the short (near) and long (far) path — that swaps when you flip the tube. The longest path = the corner diagonally opposite the mirror column.
Rotates the tube 180°. On your Fusion Pro the tube sits at the back and fires to the operator's left, so M1/M2 and the gantry rail live on that side. Use the FRONT marker in the scene to orient yourself, and flip if the view is mirrored from your machine.
Beam landing on the material vs. where it should be. Zero tilt = dead center. The further the head, the more a small tilt is amplified.
Where the beam strikes each mirror face (orange) vs its center (crosshair) — the cyan ring is the mirror's clear aperture. M1 is skipped: it's the first mirror after the fixed tube, so the beam always hits it dead-center no matter what you adjust. Its slot shows the material landing (end of path) instead — crosshair = intended, dot = where the beam actually lands.
After the lens the beam converges to a waist (the focus), the rays cross, then it diverges again — an hourglass. The lens sets how tight that waist is and how deep the focus reaches: a short lens (1.5″) gives a tiny, intense spot but shallow focus; a long lens (4″) gives a bigger spot but reaches through thick stock.
"Set focus" is what you dial in (cyan dashed line). "Actual focus" is where the waist really lands once beam-path drift is included — move the head and watch it separate from the dialed-in value.
Full optical model: Gaussian divergence along the real path, aperture clipping at every mirror, then the focusing lens below M4.
Beam color is visualization only — a 10.6 µm CO₂ beam is invisible IR. Divergence and beam width are scaled up in 3D so the effect is visible; readout numbers are true scale.
Tube (bottom) fires horizontally → M1 folds it up → M2 turns it along the Y rail → M3 (Y-gantry) turns it along the X rail → M4 (head) sends it down through the lens to the material.