# OFFSET in AutoCAD

> How AutoCAD's OFFSET (O) works, prompt by prompt: a distance or Through, Erase and Layer, one object and one side at a time. Try it free in your browser.

OFFSET draws a copy of an object parallel to it, at a distance you type or through a point you pick: a line gives a parallel line, a circle or an arc a concentric one, a polyline an outline inside or outside it, an ellipse or a spline a spline that follows it. As in AutoCAD, it takes one object at a time: you give the distance once, then pick an object and the side to put its copy on, as many times as you like. Enter ends it.

- **Command:** `OFFSET`
- **Aliases:** `O`
- **Panel:** [Modify](https://mellowcad.com/docs/commands.md#modify)
- **Try it:** [Open the editor](/draw), type `O` and press Enter.

## At the command line

The engine draws it and writes its history as you would type it: the prompts in AutoCAD 2027's order, with the same option letters.

A rectangle offset 6 inside and a circle offset 6 outside, each picked, then its side.

```text
Command: OFFSET
Current settings: Erase source=No  Layer=Source  OFFSETGAPTYPE=0
Specify offset distance or [Through/Erase/Layer] <Through>: 6
Select object to offset or [Exit/Undo] <Exit>:
Specify point on side to offset or [Exit/Multiple/Undo] <Exit>:
Select object to offset or [Exit/Undo] <Exit>:
Specify point on side to offset or [Exit/Multiple/Undo] <Exit>:
Select object to offset or [Exit/Undo] <Exit>:
```

## Options

### `Through` (`T`)

Instead of a distance, each copy passes through a point you pick or type. It is the first prompt's default, so Enter there chooses it until a distance has been given; from then on Enter repeats the last distance, in that drawing.

### `Erase` (`E`)

Asks whether to erase each source object once it is offset, `Yes` or `No` (the default). With `Yes`, the copy replaces the object. The choice is kept for the rest of the session, and the next OFFSET says it in its first line.

### `Layer` (`L`)

Asks where the copies go: on the `Current` layer, or on the `Source` object's (the default). Kept for the session too.

### `Exit` (`E`)

Ends the command, as Enter does at the object prompt.

### `Multiple` (`M`)

At the side prompt: keep offsetting the same object without picking it again, each copy one distance further out from the last, until Enter or `Exit`.

### `Undo` (`U`)

Takes back the last copy, whichever object it came from, and asks for an object again. With no copy left to take back, it says so.

## What it does not do yet

OFFSETGAPTYPE 1 and 2: the corners of an offset polyline are always closed as with 0, the segments extended to meet. A spline's or an ellipse's offset is within AutoCAD's tolerance, but its knots fall where MellowCAD puts them, not where AutoCAD does. Through on a spline shows X and Y in its tooltip, not the distance.

[What it does and still lacks, in detail (in English)](https://github.com/ovelilla/mellowcad/blob/main/docs/coverage/modify.md#offset--o--es-desfase--df--eq--pt-br-deslocamento)

## Questions

### What is the shortcut for OFFSET in AutoCAD?

`O`, then Enter or Space. The full name works too, and `_OFFSET` in any language of AutoCAD.

### Why can't I offset an object?

OFFSET offsets lines, arcs, circles, 2D polylines, ellipses and splines. It refuses text, multiline text, block references, dimensions and hatches with `Cannot offset that object.`, and so it does when the distance would shrink a circle, an arc or a polyline to nothing. An object on a locked layer cannot be picked, and a 3D polyline is passed over.

### How do I offset the same line several times?

Pick the line, then type the letter of `Multiple` at the side prompt: each pick on that side makes one more copy, each a distance beyond the last. Or keep the default and pick the newest copy each time.

### How do I put the offset copies on the current layer?

Choose `Layer` at the first prompt, then `Current`. From then on every copy goes on the layer that is current, until you choose `Source` again.

## Related commands

- [TRIM in AutoCAD](https://mellowcad.com/docs/commands/trim.md)
- [EXTEND in AutoCAD](https://mellowcad.com/docs/commands/extend.md)
- [FILLET in AutoCAD](https://mellowcad.com/docs/commands/fillet.md)
- [COPY in AutoCAD](https://mellowcad.com/docs/commands/copy.md)