Dimension Diameter

The dimdiameter command places a diameter dimension on an arc or circle. The dimension line spans the full diameter — passing through the center between two diametrically opposite arc points — and is labeled ⌀ <value>. To annotate just the radius from center to one edge, use Dimension Radius.

Anatomy of a diameter dimension

  ●──────────── ⌀ 10.00 ────────────●
  (far arc point)              (near arc point / text side)

• Dimension line — spans the full diameter, with arrowheads at both arc-intersection points.
• Near arc point — the circumference point on the cursor side (where the text label sits).
• Far arc point — the diametrically opposite point.
• Label — ⌀ followed by the diameter value.

Placing a diameter dimension

1. Type dimdiameter in the terminal or click the Dimension Diameter toolbar button.
2. Click an arc or circle to select it.
3. Move the cursor to rotate the dimension line to the desired angle.
4. Click to place the dimension.

Only Arc and Circle entities can be selected.

Keyboard reference

Dimension Diameter vs Dimension Radius

Editing the label — simple mode

Double-click a placed diameter dimension to open the text editor in simple mode. The editor is pre-seeded with the current rendered value (e.g. ⌀ 10.00) so you can position the cursor and edit it directly.

See Text Editor — simple mode for the full reference.

DXF — DIMENSION diameter entity

Diameter dimensions are saved as DIMENSION entities with diameter-type geometry, storing both arc-point positions and the measured diameter value (2 × radius). All properties round-trip without loss.