2D — wireframes, cut paths, and DXF and PDF drawings in

New · Shop-ready drawings

Every dimension toleranced — shop-ready drawings

Send a shop a sheet it can quote without picking up the phone. NativeCAD puts a tolerance on every dimension, calls out the mounting holes for the screws that go through them, and stamps the same title and tolerance block on every drawing you send that supplier.

Before a plain auto-dimensioned sheet

59 of 59 dimensions untoleranced

After shop profile ASME inch · GD&T · CNC

37 of 37 dimensions toleranced · 0 errors

PDF heatsink-nc-hs-906.pdf 217 KB

Every dimension toleranced

Each number on the sheet has exactly one tolerance behind it: its own, the general block, or a feature control frame. A drawing with a gap in it is caught before it leaves, not when the parts come back.

Position tolerances sized from the hardware that mates

The heat sink's four mounting holes are called out for a #4 screw: ⌀.123–.133 thru, position ⌀.011 at MMC to A|B|C. Tight enough to assemble every time, open enough to quote as standard CNC work, with the wall around every hole checked.

One title and tolerance block per supplier, on every sheet

Save a shop profile once — title block, general tolerances, revision table, corner stamp — and every sheet for that supplier carries it, identically. Ready to go: ASME inch, ASME metric and ISO 2768-m.

“Using the same global tolerance block on every drawing you send to the same factory matters more than it seems.”

“Keep GD&T on the mounting holes, but size the position tolerances realistically for the parts that mate.”

— Manufacturing engineer, NativeCAD tester

What we shipped in response:

• Shop profiles — one saved title and general-tolerance block per supplier, stamped on every sheet.
• Hole position from the fastener — sized for the screw that mates, floating or fixed.
• Tolerance coverage — no dimension leaves without a tolerance.
• Automatic datums and profile — with the GD&T table on the sheet.

The part is the heat sink NativeCAD rebuilt from NIST's public test drawing 827-9999-906; the sheet, part number NC-HS-906 and title block are NativeCAD's. See it built from the drawing →

Wireframe — cad_export_body format:"svg" | "dxf"

Two view modes, same writers. The default is a projected wireframe of the tessellated mesh's edges — every edge, precisely labelled. view:"hlr" (shipped 2026-08-29) routes the already-attached tessellation through the kernel's HLR classifier (ops/hlr.js) instead — no extra tessellation pass — and produces an actual hidden-line-removed drafting view: visible B-rep edges and silhouettes solid, hidden edges dashed, each occlusion-tested against the whole body by camera raycast from the chosen axis. The response reports visibleEdgeCount/hiddenEdgeCount; the default wireframe output is byte-identical to before this shipped.

Cut paths — cad_export_body format:"contour-dxf"

Takes the boundary of the planar face facing the viewer straight off the B-rep and writes closed contours as true LINE/ARC/CIRCLE entities on a single CUT layer — no mesh, no facets, no text — plus bend centrelines on BEND_UP/BEND_DOWN layers for a formed sheet-metal part. It needs a flat-cut part (one planar face normal to the view axis, all features through), and returns warnings naming anything it could not honour — a blind pocket, say — instead of silently drawing it as if it were a through-cut.

DXF in — cad_import of a .dxf

The short version, with a sample to try and what the vector-PDF reader adds: DXF & PDF import. This section is the full reference.

A laser-cut drawing in, a flat part out. cad_import reads an ASCII DXF and chains its LINE, ARC, CIRCLE, LWPOLYLINE, POLYLINE, ELLIPSE and SPLINE curves — block INSERTs and MINSERT arrays expanded, mirrored and non-uniformly scaled ones included — into closed loops: an outline plus the holes nested in it. A loop inside a hole is an island and becomes its own part. What you get is decided by the options:

thickness, layers, excludeLayers and gapTol belong to DXF: on any other extension they are refused by name, never silently ignored.

Exact where the file is exact. Holes are cylinders, not N-gons. An ELLIPSE and a control-point SPLINE (weights included) are carried as exact B-spline edges on extruded walls. The one caveat is the fit-point-only SPLINE — a file that stores the points the curve passes through and no control points has no exact form on disk. It is sampled along the reader's interpolation, the loop is flagged approximated, chain.approximatedLoops counts it and a warning names it.

Nothing is dropped silently. The report lists every layer with its entity count, what the reader skipped by entity type (3DSOLID, 3DFACE, polyface meshes, POINT), the gaps it healed, duplicate outline segments removed, open chains with the gap between their ends, and any closed loop withheld because it sits inside an outline that never closed. DIMENSION, TEXT and HATCH are read as data on the report and never become geometry. An open chain is a warning, not a crash: the closed profiles import and the open ones are listed, so an agent can raise gapTol or fix the drawing.

In the modeler. Open… (or drag and drop) a .dxf and the dialog shows what the file holds before anything is built: a preview of the closed profiles and the open chains, the units the header declares, and under them the size the header claims next to the size the drawing itself measures — a stale header, or a wrong unit, is called out before you press Import. A file that looks like a sheet (a title block, views placed in projection, a paper-space layout with viewports) is offered Read as a drawing; it never switches for you, and Part or sketch stays one click away. In drawing mode a Sheet box reads the model space or any paper-space layout, and Add summary to the log, Copy summary and Download JSON keep what it found: views, projection, scale, title block and layers, as data, the same bytes for the same file and options. The summary is not saved with the project — download it to keep it.

Out of scope, by name: 3D entities (counted, not converted), binary DXF and DWG, splitting curves at T-junctions (a drawing built from crossing lines is trimmed first), and more than one thickness per import — bends and different gauges belong to the sheet-metal verbs. Only the model space builds a sketch or a flat part.

PDF drawing in — cad_import of a .pdf

The short version, with the DXF reader beside it: DXF & PDF import. This section is the full reference.

Most manufacturer and datasheet drawings are vector PDFs: the outlines are exact path operators and the dimensions are real text. NativeCAD reads one page of one as a drawing, not a picture, and answers exactly what the same sheet as a DXF answers — so a supplier's PDF is something you can ask questions of instead of something you look at. The .pdf here is a flat drawing: a 3D PDF's embedded model (the PRC the pdf writer produces) is not read.

• Exact outlines. Lines, arcs and circles come back as LINE, ARC and CIRCLE records in sheet millimetres. A PDF has no arc operator, so an arc is recovered from the Béziers it is drawn with; any other Bézier stays an exact cubic SPLINE, never a polygon. Measured against drawings NativeCAD makes itself, every visible segment comes back within 0.001 mm on the sheet.
• The sheet's structure. The views (front, top, side, iso, sections, details), where each sits, first or third angle with a confidence, and each view's own scale, recovered from its dimensions.
• The annotation. Every dimension value (60, Ø8, R4.75, 2X Ø2.5, 30±0.1, 45°) paired with its own dimension lines, the title block's fields, the notes and the border.
• The line roles. The PDF's own optional-content layers when it has them; when it has none, the stroke style: dashed is a hidden line, chain is a centre or phantom line, and a thin continuous stroke is annotation, so dimension lines never become views of their own.

thickness, gapTol, space and layout belong to DXF: with a .pdf they are refused by name, never silently ignored — a PDF is a drawing, not a cut path, and it has pages, not model and paper space.

Nothing is dropped silently. The report gives the page (index, count, size, rotation), every layer with its role, the reader's own scale vote, the unit the dimension text came from, and what the reader skipped and counted: filled-only paths, clipping paths, images, shadings, invisible OCR text. A page that is a scan is not guessed at from pixels.

In the modeler. Open… (or drag and drop) a .pdf and it opens straight in the drawing panel: page 1, with a Page box for the others, the same views table and title block a DXF sheet gets, and Add summary to the log, Copy summary and Download JSON to keep what it found. It is read-only: nothing is added to the model. A refusal appears in the dialog with its code. From Claude, cad_import reads a .pdf from the first plugin release that carries the page field (tool schema 1.42.0); until you have that release, use the modeler.

Out of scope, by name: a 3D PDF's embedded PRC / U3D model, text drawn as outlines (a title block set in outlined glyphs has no fields), images and shadings (counted, not traced). On a sheet whose dimension text is in inches, a view's scale measured from its dimensions reads them as millimetres and comes out 25.4× too large; a warning says so, and a title-block SCALE stands. Rebuilding the part from its views is the drawing → STEP step, not this import.

Try it

CUT DXF nativecad-plate-cutpath.dxf 1.4 KB DXF nativecad-plate.dxf 365 KB SVG nativecad-plate.svg 300 KB

The size gap tells the story: the sample plate's cut path is 6 closed contours in 13 entities — 1.5 KB of arcs and circles a vendor's CAM reads directly — while the wireframe of the same part is thousands of tessellated edges.

DXF import is an import-only spoke, so it has no kernel-authored sample of its own. Its round-trip input is the cut path above: hand nativecad-plate-cutpath.dxf to cad_import with thickness: 6 and the sample plate comes back — one watertight solid, 20 faces, 12,293.80 mm³, the five holes real cylinders, named CUT from its layer. tests/test_dxf_import.js asserts the same round trip on the kernel's own plate: volume within 1e-6, the same face and hole counts.