SketchLin the studio

Line

Line draws a chain of straight lines in the sketch editor, one corner per click or per typed length. A click back on the first corner, or C, closes it into an outline, and Enter ends it open.

What it is

Line draws straight lines corner to corner in the sketch editor. Each click places a corner and the next line starts there, so a run of clicks is one chain. The chain closes into an outline when you come back to its first corner, or it stays open when you end it. From the third corner on, the shape in progress is drawn filled, closed back to the pointer, so you see the outline you are about to make.

The dimmed shape in force behind your drawing is a magnet: corners, middles and edges of it, of your own lines and of their crossings all attract the pointer, and so do the lines of the view.

When to use it

Drawing a new outline with straight sides, such as a pointed window, a trapezoid or an L-shaped area.
Adding a single straight line across a shape, to divide it or to trim against later.

The steps

Arm Line. In the sketch editor (see Select for the ways in), press L or click Line on the editor's toolbar. Its button lights up on the toolbar. The hint at the cursor says first point.
Click the first corner. It snaps to what is near, and the snap shows on the pointer.
Click the next corners. A line follows the pointer from the last corner and the hint shows its length. Each click places a corner. You can also press, drag and release: the release places the next corner. For an exact length, point in the direction of the next side, type the length in the project's units and press Enter. Backspace takes back the last character typed, or, with nothing typed, the last corner placed.
Close the outline. Click the first corner again, or press C once there are at least three corners. The closed outline stays, and Line is ready for a new chain.
Or end it open. Press Enter or click the right mouse button to end the chain where it is and stay in Line. Space or Escape also end it open and go back to Select. A chain needs two corners to stay; with a single corner, Escape drops it.

What it refuses

The same corner twice in a row. A click on the last corner does nothing.
A length typed before the first corner. Digits count only once a chain has started. Typed before, they are dropped.
Coordinates. Line takes a length along the pointer, not a point typed as numbers. To type points, use Polyline.
Closing with too few corners. C needs three corners; with two, it does nothing. Enter with only one corner does nothing either.
The shape in force. Your lines snap to it but never change it. It is not part of your drawing unless you draw over it.

What it writes to the contract

Nothing until you press Done. Each chain is added to the drawing inside the editor, its corners rounded to the millimetre, and Ctrl+Z steps back through them. The contract changes when you press Done, or Enter with nothing in progress, as one step you can undo. Done reads every area your lines enclose, wherever they cross or touch, and it must find exactly one outline with no island. That outline becomes the window's or door's profile, points [u, v] in metres across the wall and up from the floor, or the pattern area's outline in the room's floorAreas or ceilingAreas, points [x, y] in plan metres. A pointed opening drawn as five corners comes out like this:

Common questions

How do I close the outline I am drawing?

Click back on its first corner, or press C once you have at least three corners. Enter, Space, Escape and the right mouse button end the chain open instead.

How do I draw a side of an exact length?

After a corner, point in the direction of the next side, type the length and press Enter. The next corner lands at that distance along the pointer's direction.

Does an open chain count as an outline?

Only where its lines enclose something with the other lines of the drawing. Done reads every area the lines close in, so a chain whose ends land on an existing line can finish an outline without being closed itself.