Devices

A device is a layout-view box representing a real physical thing the harness plugs into — an ECU, a PDM, a splitter box, a PCB. Connectors mount onto it and move with it, so your layout reads like the actual installation instead of a cloud of floating connectors.

Devices are purely a layout and documentation element:

• They exist only in the layout view — the schematic never shows them.
• They never affect wire routing or lengths. Bundles, breakouts, and the cut list are computed exactly as if the device weren’t there.
• If a device has a part number, it appears as a line item in the BOM.

Harness files saved before devices existed open fine — LoomFlow upgrades them automatically when it loads them.

Create a device

In the layout view, right-click empty canvas and choose ＋ Device here. A box appears (default 260 × 180) labeled Device, already selected so the Inspector opens on it.

From the Inspector you can set:

Field	Effect
Label	The name drawn in the box header (e.g. “ECU”, “PDM”)
Part number	Adds the device to the BOM as a purchased item
Manufacturer	Shown alongside the part number in the BOM description
Width / Height	Box size in layout units
Exclude from BOM	Documented but not purchased — the BOM skips it

To resize interactively, select the device and drag the resize handles on its border (minimum 90 × 70). One resize is one undo step.

Mount connectors on a device

Drag a connector (or terminal, splice, or junction) so its center lands inside the device box, then release — it mounts. Drag it back off the box and it unmounts. If devices overlap, the topmost one in draw order wins.

Mounted nodes become children of the device on the canvas:

• Dragging the device moves everything mounted on it as one unit.
• Mounted connectors stack on top of the device box, so they stay visible over a background image.

The Inspector’s Mounted section lists every node on the device; click an entry to jump to that node’s inspector. To detach everything at once, right-click the device and choose Unmount N connectors.

Right-clicking a device also offers Edit in Inspector…, Copy device, and Delete device. Deleting a device unmounts its connectors but leaves them (and their wiring) in place. Delete/Backspace on a selected device does the same.

Add a background image

A device can display an image — a photo of the enclosure, a board render, a connector-face drawing — filling the box behind the mounted connectors.

In the Device inspector, click Set image… and pick an image file (PNG, JPEG, GIF, WebP, BMP, or SVG). Replace image… and Remove image manage it afterward.

Device images are bundled into the project file: when you add one, it’s packed inside the .loomflow container along with the document, which stores the asset’s name and natural pixel size. A project stays a single portable file — there’s nothing extra to carry alongside it.

Note

Images are held in memory as you work and written into the .loomflow file when you save, so you can add them any time — no need to save first. In the browser version an imported image renders immediately; save the project so it’s bundled into the file and re-opens correctly.

Tip

Because the image lives inside the project file, sharing a design with photos is just sending the one .loomflow — the image travels with it, and a teammate who opens it sees exactly what you do.

Devices in the BOM

The BOM leads with a device category. Each device that has a Part number (and isn’t marked Exclude from BOM) contributes one line, grouped by part number — two boxes with the same part number become one row with quantity 2 ea. The description is the part number plus the manufacturer in parentheses.

Devices never appear in the cut list: they contain no cavities and no bundle attaches to them, so lengths are unaffected. See exporting for the BOM and cut-list outputs.

Devices in exports and imports

Technical drawings — exported drawing sheets render devices as dashed boxes with an italic label (and part number, when set). A whole-layout sheet includes every device; a per-harness sheet includes only devices that have a connector from that harness mounted on them. See exporting.

KiCad import — when importing a .kicad_sch, the review dialog offers Mount all on a new device, checked by default. The device name is prefilled from the sheet title (or file name), so a board schematic lands in the layout as a box with all its connectors already mounted. See importing.

Copy/paste — devices participate in canvas copy/paste like nodes and notes. Select a device together with its mounted connectors to carry the whole assembly to another spot, another document, or another running instance.

Where devices fit

Use devices when the layout should show what the harness connects to, not just the harness itself. They pair naturally with harness groups — a device often marks the boundary where one harness ends and equipment begins. For the layout view fundamentals (bundles, trunk lengths, breakouts), see layout.