Bend — round a square corner into an arc

What does this tool do?

Bend turns a square corner of a board into a round arc running through the full thickness — a roundover for curved cabinets, doors and panels. Hold Shift to switch to a concave arc (cove) instead of convex.

The tool works on:

• Board groups/components — the arc is cut with a solid boolean, so the curved face is seamless with the board.
• Flat 2D faces or outlines (loose faces/lines, no solid yet) — the corner is cut into an arc right on that face.

Use it when you need to:

• Round a visible corner of a cabinet side, top or countertop for safety and looks.
• Create a curved form to later flatten with Unfold for CNC kerf cutting.
• Round a corner to an exact radius in millimetres instead of drawing an arc by hand.

Basic steps

1. Click the Bend icon on the toolbar.
2. Hover over a board face, near a right-angle corner. Once the cursor is inside the corner's pick zone, the corner edges light up cyan and a blue preview arc appears, wrapping through the board thickness.
3. Click to bend that corner at the current radius.

After the click the tool stays open: move to another corner to bend it too. Press Esc to exit. Each bend is one Undo step (Ctrl+Z).

Entering radius and segment count

The input box in the bottom corner (VCB) is labelled R(mm), Segs. Just type, no need to click the box:

• 200,24 — 200 mm radius, arc divided into 24 segments.
• 150 — change only the radius to 150 mm, keep the segment count.

Notes:

• The default is 50 mm, 12 segments; values you type are remembered for next time.
• The segment count is clamped to the radius (at most about R×2/3, never over 360), so a small arc cannot be over-divided into hundreds of heavy edges.
• More segments means a smoother arc but a heavier model; 12–24 segments is plenty for most cabinet corners.

Convex or concave — hold Shift

By default the tool rounds convex (removing the sharp corner tip). Hold Shift to flip to concave: the arc bites into the board like a cove. The preview flips the moment you press or release Shift, so always check it before clicking.

Keyboard

• Click – bend the corner under the preview.
• Type radius,segments + Enter – set R and segments (e.g. 200,24).
• Shift (hold) – flip convex/concave.
• Esc – exit the tool.

Common problems

• No preview arc: the cursor is too far from the corner. The pick zone around the cursor equals the current R (at least 50 mm) — move closer to the corner, or raise R to grab corners from further away.
• "Radius too big" error: R is larger than one of the two edges forming the corner (the arc does not fit). Lower R or pick a corner with longer sides.
• The arc looks faceted: too few segments for the radius. Raise the count (e.g. 200,32).
• Bent the wrong way (convex/concave): check the preview before clicking; Ctrl+Z and bend again with (or without) Shift.
• Corner is not square: the tool only accepts 90° corners; an angled corner shows no preview.