Part Digitizer

Tools ▸ Part Digitizer · ■ Blue · needs a bed photo

What it does

Photograph a part lying on the bed, press Digitize the part, and ALPS drops a closed vector of that part's outline into the job — at the photo's own bed position and scale, so it lands where the part actually is.

⚠ What the result is worth, before you use it for anything

It is a proposal, not a measurement. Expect roughly ±40 thou.

That is not modesty. The limit is segmentation — deciding which pixels are the part and which are the bed. Four methods run on one capture disagreed by 42 to 338 thou, and even the two best modern models still differ from each other by 42 thou. The camera is not the bottleneck; the judgement about where the edge is, is.

⭐ So the digitizer proposes and the review measures. Run Outline Review over the result and the same outline becomes good to 1–2 thou wherever the edge is actually visible. The two are deliberately separate tools: this screen never claims an accuracy, and the review is where a number is earned.

⛔ Do not cut an expensive part straight off a digitize. ±40 thou is fine for a rough jig blank, a nesting placeholder, or seeing the shape. It is not fine for anything that has to fit.

Step by step

1. Put one part on the bed. One — the tool segments a single subject.
2. Capture a bed photo, or import one.
3. Open Tools ▸ Part Digitizer and pick the photo.
4. Digitize the part.
5. The outline arrives in the Job Editor, positioned where the part was.
6. Run Outline Review on it before trusting a dimension.

Getting a good result

The whole job is making the part obvious against the bed:

• Contrast. A dark part on a dark bed is the hard case. Put a sheet of paper or a contrasting board underneath — it costs nothing and it is the single biggest improvement available.
• Flat lighting. Shadows read as part of the part. A shadow with a soft edge is usually rejected, but a hard one under a raised edge is not.
• The part flat on the bed. Anything standing proud is photographed from an angle and its outline is measured at the wrong height. See the warning below.
• Nothing else in frame — no fingers, no clamps, no other parts.

⚠ Height is the error nobody expects. The camera sees a part from slightly above, so a tall part's top edge does not sit over its bottom edge in the picture. A part 0.6" thick can read several tens of thou wrong for that reason alone. Digitize thin things, or expect the outline to describe the top face rather than the footprint.

Related

• Outline Review (outline-review.md) — the other half. Turns this proposal into a measurement.
• Fixture Maker (fixture-maker.md) — if what you want is a jig rather than the part's outline, go straight there; it is built for that and does not need this level of precision.
• Shape Match (shape-match.md) — if the part is a known simple shape and you want artwork placed onto it, that is the better tool.