Inspect interiors with cutaway and onion

A bounding volume with cutaway on hides everything outside its box. The box's faces become cut surfaces straight through your model — the fastest way to look inside a lattice, check a wall thickness, or see whether two internal parts actually meet.

Turn the cut on and off

Cutaway is a per-volume toggle — on the volume's panel row, mirrored on its scene-tree row. Only the active volume (●) cuts, so several volumes can carry the flag and the cut still has one owner. A new volume starts with cutaway on.

Hiding a volume (a click on its icon in the scene tree) also hides its cut: an invisible volume never slices your view from off-screen.

The onion bands

Rest the pointer on a cut face and concentric bands fade in — an onion of contour lines. Each band marks a step of equal distance into the material, measured in real millimetres, like elevation contours on a map.

That makes the bands a measuring tool, not decoration:

• Count bands between the cut surface and a feature and multiply by the spacing — that is the material depth to the feature.
• Set the spacing to a tolerance you care about (say 2 mm) and any wall thinner than one band is instantly visible.

The onion spacing field on the volume's row sets the step. 0 means automatic — a round fraction of the box's smallest extent. The bands do not move or animate; what you see at rest is the pattern, and hovering only fades it in.

Where the bands come from

The bands are computed from your model's real signed-distance field — the same field that renders the surface and meshes exports. They are not a texture painted on; if a band looks wrong, the field is wrong, which is precisely the kind of thing this view exists to reveal.

Cost

The onion shades only while a cut face is hovered. Expect a moderately heavier frame while it is showing (the interior distance is a second field evaluation); moving the pointer off the volume returns to the normal cost.