Offset

The offset command creates a parallel copy of an entity at a fixed perpendicular distance. You type the distance once, then click entities and pick a side — the command stays ready at the same distance so you can offset multiple objects in one session.

Supported entity types: Line, Circle, Arc, Ellipse, Polyline (including Rectangles).

Using offset

1. Type offset in the terminal or click the Offset toolbar button.
2. Type the offset distance and press Enter or Space.
3. Click an entity to offset — if the entity is not a supported type, an error message appears and you can click a different entity.
4. Move the cursor to the side where the copy should appear — a live preview follows.
5. Click to place the offset copy.

After each placement the command returns to step 3 at the same distance, ready for the next offset. Press Escape to reset back to the distance-entry step.

  Distance: 10

  ─────────────────    ← original line
  ─────────────────    ← offset copy (10 units below)

Per-entity offset behaviour

Entity	How the offset is computed
Line	Parallel line shifted perpendicular to the original direction
Circle	Concentric circle; click outside → larger radius, inside → smaller radius
Arc	Concentric arc at a new radius; same angular span preserved
Ellipse	Both semi-axes increased or decreased by the same distance
Polyline	Each segment offset independently; adjacent offset segments are mitered at corners

For Circle, Arc, and Ellipse: if the inward offset would reduce any radius or semi-axis to zero or below, the offset is not applied.

Keyboard reference

Key	Action
0–9, .	Append digit to the distance value
Backspace	Delete last typed character
Enter / Space	Confirm the typed distance and advance to entity selection
Escape	Reset to distance-entry step

Workflow note

The distance stays set until you press Escape. This makes it efficient to offset many entities at the same spacing — type the distance once, then click and pick side for each entity in turn.

Offset vs Copy

	Offset	Copy
Displacement	Perpendicular to the entity's geometry	Arbitrary vector (base → destination)
Supported entities	Line, Circle, Arc, Ellipse, Polyline	All entity types
Distance input	Typed before selecting the entity	Typed or clicked after selecting
Best for	Parallel lines, concentric circles, inset/outset paths	Placing duplicates at arbitrary positions