One flat part in. Measured for real by the browser, then read, checked against the process, corrected, and made orderable.

Not until you run an AI lane. A dropped .dxf is read with FileReader in your own tab and parsed there. The reader, the contour stitching, the geometry, the rule checks and all six exports are free, offline and need no account. When you do run a lane, what is sent is the facts block the browser measured plus an excerpt of the DXF text, cut on whole entity boundaries. Part geometry is commercial property, so the saved draft and the history mirror in this browser are keyed to your account and are deleted when you sign out.

It parses it. A DXF is a flat stream of group code and value pairs, two lines each, so the reader tokenises pairs first and interprets second. It reads HEADER variables, the LAYER table and the BLOCKS section, and expands every INSERT into model space with that insert's own translation, rotation and scale, recursively, to a bounded depth. A CIRCLE inside a block inserted with a uniform scale stays a circle with an exact diameter; under a non-uniform scale it is an ellipse, so it is discretised in the block's own frame and the points are transformed — which is geometrically right, unlike scaling a radius — and the approximation is reported. Polyline bulges are turned back into real arcs, because a bulge measured as a straight chord understates a rounded rectangle's perimeter by several per cent. A binary DXF or a DWG is refused by name with instructions, not parsed into nonsense.

Because an open contour has no inside. A cutter is told to follow a path and keep the material on one side of it; if the path does not close, there is no side, and the file is rejected or — worse — cut as an unclosed slit. It is the most common reason a flat-part file comes back from a shop. The reader stitches every cut entity into chains, closes the ones whose endpoints meet within a stated tolerance, and lists the rest with the size of the gap and both endpoint coordinates so you can go straight to them in CAD.

They are real published sheet-metal guidance and they are not your shop's catalogue. Every limit in this app is a ratio applied to your material thickness — a laser-cut hole in metal wants a diameter of at least one material thickness, a flange wants about four, an opening wants about two and a half thicknesses of clearance from a bend — and the app shows the ratio, the thickness and the resulting limit next to the measured value every single time. This app has no network access and cannot fetch a vendor's price list, so it never pretends to have one. Treat the numbers as the conservative starting point and confirm them against the shop's own published specification before you order. No price is quoted anywhere in this app.

Read establishes what the file actually contains: what the part is, what the units are, what each layer means, what each contour is for, and which of the browser's readings are guesses that still need settling. Check it will cut takes the process, material and thickness you picked and reviews every measured value against its limit, names the consequence of each violation and its remedy, and lists the secondary operations the part implies. Correct the part produces the specific edits that clear the findings plus a parametric build123d script that regenerates the corrected part and exports DXF and STEP, so the fix is repeatable rather than a one-off nudge in CAD. Build the order packet produces the order as a shop needs it: material, thickness, quantity and finish, the services in the sequence they happen, the hardware, the quantities a quote is computed from, the questions to ask, and the pre-upload checklist. All four run over the same file and each result offers the next lane as a button.

The browser measures first and sends its numbers into the run. The model must return one reconciliation entry per critical and high flag by id, so a defect it ignored is displayed as unaccounted for rather than quietly dropped. Every contour, layer, bend and rule id it cites is checked against what the file contains, and one that does not exist is shown, marked, rather than trusted. Every layer name the script it returns reads is checked the same way — including the ezdxf query idioms, not just the obvious one — while a layer the script itself creates is not flagged. On the read lane, any layer carrying geometry that the reading does not mention is listed as a hole in the reading, because anything not read is cut by default. On the check lane, any rule the browser measured as failing that the review passed over in silence is listed too.

It does not nest your parts on a sheet, and it does not price anything. It does not evaluate spline basis functions: a spline is measured through its fit points, or failing that along its control polygon, which is an outer bound — so a spline contour can only ever be reported as longer and wider than it is, an error that never turns a real violation into a pass. It cannot measure an inside bend radius from a flat pattern, because that is a tooling choice rather than a property of the drawing, so the radius is listed as a rule the flat pattern must have been developed against rather than as a measurement. And it never rewrites your original file: the cut-only DXF it can write is a new file for you to check in CAD.

A worst-case amount is reserved before you run and only what the run actually uses is charged. The estimate is checked against your balance before the button enables: signed out, it says signing in comes first; under the model's minimum, it names the exact shortfall; and a reply cut short by a low balance says so rather than presenting itself as complete. The whole browser side is free and needs no account at all.