# Fit a carcass into an alcove

Model the space as an envelope, fit a carcass inside it with clearances or scribe fillers, and refit it when the space changes.

An envelope is the space that the furniture goes in: an alcove, a recess or the space under a slope. A carcass fitted to an envelope takes its width, height and depth from it, less the clearances.

To see a finished example, open **File ▸ Sample projects ▸ Alcove shelving**.

## Make the envelope

Use one of these methods.

### Type the sizes

1. In the **Model** tree, click **+ envelope…**.
2. Click a shape: **Box**, **Sloped**, **Profile** or **Hull**.
3. Type a **Name**.
4. For **Box**, type the **Width**, **Depth** and **Height** in mm.
5. For **Sloped**, type the **Tall end** and the **Low end** heights too.
6. For **Profile**, set **Drawn on** to **front**, then type the **Profile points** and the **Depth**.
7. Set **Dimensions** to **measured**, **estimated** or **assumed**.
8. Click **Create**.

### Draw it

1. Click **⬚ Envelope** in the toolbar, or press E.
2. Click the points of the outline. You can type each length.
3. Click the first point again, or press Enter, to close the outline.
4. Move the pointer to push it to a depth, then click. You can type the depth.

The tool card on the toolbar lists the keys for each step. A carcass fits only a **Box**, a **Sloped** envelope or a **Profile** drawn on the front plane. It does not fit a **Hull**.

## Set the boundary

**The assistant's boundary** is on by default. With it on, the assistant must keep what it builds inside the envelope. If you move a part outside, the status bar shows a warning, but KerfCraft does not stop you.

To change it, select the envelope and use the **Boundary** box in the **Properties** panel. You can also right-click the envelope and click **Use as the assistant's boundary**.

## Fit the carcass

1. Select the carcass. To make one, see [Build a cabinet, bookcase or wardrobe](/docs/how-to/furniture/build-a-carcass/).
2. In the **Properties** panel, at **Envelope**, click **Fit to envelope…**.
3. At **Envelope**, select the envelope.
4. If necessary, change **Clearances › Left**, **Right**, **Top** and **Back**.
5. Click **Fit**.
6. Read the warning in the form, then click **Close**.

The form shows a warning about the envelope. If the envelope is measured, it tells you to check the diagonals. If it is estimated or assumed, it tells you to measure the space. The status bar also shows the warning.

The defaults are 10 mm at the left, the right and the top, and 0 mm at the back. The front of the carcass is flush with the open front of the envelope. The carcass remembers its envelope, and the button changes to **Fit again…**.

If the button is not available, draw an envelope first.

In a **Sloped** envelope, or a **Profile** with a sloped top, the top of the carcass follows the slope. The profile top must be one straight line across the carcass. If the slope changes inside it, KerfCraft does not fit it, and tells you where to split it into two carcasses.

The assistant can also fit a carcass, for example "fit a bookcase with five fixed shelves into the Alcove".

## Add scribe fillers

Walls are rarely straight. A scribe filler is a panel between the carcass and the wall, cut oversize and scribed to the wall on site.

1. Select the carcass, and click **Fit to envelope…** or **Fit again…**.
2. Type the filler width in **Fillers › Left** or **Fillers › Right**, for example 50.
3. If necessary, change **Scribe allowance**.
4. Click **Fit**.

A filler takes the place of the clearance on its side. **Scribe allowance** is the extra width on each filler blank. The default is 15 mm.

On a fitted carcass, you can also type the width in the **fillerLeft** or **fillerRight** parameter and press Enter. KerfCraft fits the carcass again with the filler, in one undo step.

## Scribe a part that you drew

1. Right-click the panel and click **Scribe to wall…**.
2. In the **Properties** panel, at **Scribe**, select each edge that meets the wall.
3. Type the **Allowance** in mm.

The model stays at the finished size. The cut list orders the blank oversize, and the **Properties** panel shows the blank size.

## Refit after the space changes

If you resize or move the envelope, the carcass does not follow at once.

1. Select the carcass.
2. In the **Properties** panel, at **Envelope**, click **Refit**.

The status bar shows the same warning about the envelope.

## Before you cut

Walls are rarely square. If the envelope dimensions are estimated or assumed, measure the space first. Check the diagonals, and add a scribe allowance if necessary. Measure the width at several heights and depths. Then check every dimension against your own measurements before cutting.

## Related

- [Build a cabinet, bookcase or wardrobe](/docs/how-to/furniture/build-a-carcass/)
- [Use project parameters and expressions](/docs/how-to/furniture/use-project-parameters/)