Generate, regenerate, and validate 2D DXF drawings from Python build123d sources. Use for DXF files, `.py` drawing scripts, @dxf models, 2D profiles, outlines, templates, gaskets, panels, flat patterns, laser/plasma/waterjet cut layouts, and 2D drawing exports of CAD geometry.

DXF generation and validation Provenance: maintained in [earthtojake/text to cad](https://github.com/earthtojake/text to cad). Use the installed local skill files as the runtime source of truth; the repository link is only for provenance and release review. Setup This skill's commands are thin entrypoints over the cadgen distribution, which carries the Python build runtime and the JavaScript it executes. Install it once: Drawings are build123d geometry, so a drawing build loads the CAD kernel like a STEP build does (~2.5s cold; the warm daemon absorbs it on re runs). Only cadgen dxf snapshot additionally needs Node 20 or newer on PATH — it meshes the flat pattern on demand through a bundled Node one shot; a missing node is reported at render time. Purpose Create or modify 2D DXF drawings from natural language requirements or from CAD geometry, generate validated drawing artifacts, and return checked outputs. A DXF drawing's source of truth is a Python file named <name .py defining one parameterless @dxf model function. A drawing is a model. It has the same wrapper, record, freshness gate and build job a @step part has; its one output is the .dxf file; it has no geometry tree (nothing links to a drawing). Every run writes the sibling <name .dxf (or the out= the decorator names); an unchanged source is a no op; a drawing that calls a part model — bracket() inside its body — is stale whenever that part's GEOMETRY changes and current when it does not; cadgen store why <drawing .py explains the verdict; force rebuilds it anyway. The CAD Viewer and dxf snapshot read the .dxf file itself, so the file you hand a cutting service and the file the viewer renders are one and the same. The contract A @dxf function takes no parameters and returns build123d 2D geometry. The engine writes the DXF. You never construct a document, name a file, or place an entity — the same division of labor @step has. Bare shape → one CUT layer. That is the whole contract for most drawings. {layer: shape} → named layers, when the drawing genuinely has more than one CAM operation ( CUT / ENGRAVE / SCORE ). A Compound whose children are all labelled means the same thing. No parameters. Dimensions are module constants ( HOLE D = 4.5 ) or constants imported from the part the drawing derives from; a different drawing is a different file. Text is bd.Text(...) engraved OUTLINES on a marking layer, never a DXF TEXT entity: cut and marking toolchains consume geometry, and font rendering inside CAM is unreliable. Geometry must lie in the XY plane. A face taken from a solid sits at that solid's height; relocate it ( flatten.flatten face(face) , or bd.Location((0, 0, z)) face ). The engine REFUSES off plane geometry rather than silently writing its XY shadow. Output bytes are a function of the geometry. Layers are sorted by name and entities by geometric content, so an unchanged drawing rebuilds to an identical file, cold or warm, on any machine. The three DXF workflows Copy the full template for the applicable workflow from references/generator templates.md when creating a new drawing. 1. Drafted from scratch (gaskets, panels, templates, cut layouts with no 3D model behind them): a <name .py that builds sketches and returns them. 2. Flat pattern of a generated STEP part : a drawing script beside the model it derives from, with its OWN stem (one model per file — bracket drawing.py beside bracket.py ). Import the model and call it, exactly as an assembly composes a child: importing never builds, and inside the drawing's build the call returns the part's geometry (building the part first if it is stale). The drawing's record pins the part's tree, so a part edit that changes its geometry makes the drawing stale, and one that does not (a comment, a refactor, a colour) leaves it current. Constants imported from the part ( from bracket import THICKNESS ) are tracked by value the same way. 3. Flat pattern of an imported STEP (a .step / .stp with no Python source): read it with cadgen.read step , not build123d.import step . It records the file's content hash as a build INPUT, so replacing the vendor STEP makes the drawing stale on its own, with no force ; read it through build123d and the drawing stays "current" against a file that changed underneath it. Never read a STEP this project generates. Reading the .step a @step model writes is not a loop, it is a drawing whose input changes on every run of the model: the freshness gate can never say "current", every build is a full rebuild, and the flat pattern depends on what the last run left on disk. Keep source STEPs in an imported/ directory beside the drawing, committed like any other input — input path and output path being different files is the whole rule. For a STEP this project DOES generate, use workflow 2 instead: import the model script and call it, which is tracked by result and never touches an artifact. One model per file: a source declaring both a @step and a @dxf model is rejected — a drawing gets its own script. A drawing composes models, never the reverse: calling a @dxf function from a @step body is just its 2D geometry and links nothing. The viewer catalog is artifacts only: scripts never list; the .dxf the run writes is the entry the viewer renders. Use this skill when Use this skill when the user asks for DXF files, 2D drawings, profiles, outlines, templates, gaskets, panels, flat patterns, or cut layouts for laser, plasma, waterjet, or CNC routing. Use $cad for the 3D part or assembly a DXF derives from. Use $sendcutsend for SendCutSend specific upload preflight. Defaults Use these defaults unless the user specifies otherwise: Units: millimeters. The engine sets them; a drawing never declares units. Geometry lives at 1:1 scale in the XY plane. Cut profiles close. Open contours belong on bend/engrave/reference layers — generation validation enforces this (see Validation). For CAD backed parts, derive contours from the real topology with cadgen.flatten rather than redrawing them: planar faces selects, flatten face lays a face into XY exactly, union faces fuses, and flat pattern does all of it in one call. Hand drawn parametric outlines only when there is no reliable 3D topology. Kerf / tool radius compensation is flatten.offset profile(shape, amount) or flat pattern(..., kerf=...) ; never hand offset coordinates. Curves stay curves. The union and the offset are exact OCC operations, so a filleted corner exports as an ARC and a hole as a CIRCLE , kerf included. A profile that comes out as hundreds of short LINE s means something fell back to the sampled path — investigate rather than accept it. Layers carry intent: keep cut geometry and bend/fold lines on separate layers, and include "bend" in bend layer names so downstream tools classify them as bends rather than cuts. DXF layers are drawing structure, not STEP part/assembly structure. Tool Running the script (its main call) is the only door. There is no cadgen dxf build : a .dxf has no derived state a command must materialize — the file IS the product, the CAD Viewer parses it directly, and dxf snapshot meshes it on demand. The drawing's gate makes a rebuild cheap: an unchanged source whose .dxf still verifies and whose part children are unchanged is a no op, and force rebuilds anyway. The bytes are a function of the drawing's GEOMETRY, so a cold run and a warm daemon worker write the same file. Builds never wait on or cancel one another; a drawing that calls parts builds them in parallel like any parent. An imported .dxf needs nothing at all — hand it straight to snapshot or the Viewer. Use the active project Python interpreter; treat python as an interpreter placeholder, and use help for the full interface. Target paths resolve from the command's current working directory; run from the workspace that owns the artifacts with cwd relative target paths. Keep a drawing script in the same directory as the geometry it derives from, named <name .py . Flags (a model script runs itself; there is no generation CLI): force — regenerate even when the recorded output is current. verbose , json . A run answers on stdout exactly as a STEP model's does — built DXF/plate drawing.dxf or current DXF/plate drawing.dxf — with progress on stderr; json makes the result one JSON line ( outcome , document , and tree , which is null for a drawing) and the progress one JSON line per transition. One script, one drawing: run each script you want built. Do not put output paths in the @dxf function's return value; out= on the decorator is the only place a drawing names its destination (relative to the script). cadgen dxf snapshot renders a drawing's 3D flat pattern to a PNG still: It takes the .dxf document only — a model script is refused by name (run python <drawing .py , then snapshot the drawing it wrote). The command meshes the flat pattern on demand through the bundled Node one shot and renders it through the shared snapshot CLI ( cadgen.snapshot cli ) and the same headless browser runtime every rendering skill uses — so geometry and materials render identically to the CAD Viewer; the default snapshot theme differs from the viewport only by dropping the grid, origin axis and shadows. OUT — the second positional — is written exactly as given, with a relative path resolved against the current working directory. The target is deleted before the render starts and the finished image is written atomically, so: reuse one name while iterating (every read is provably the render you just ran), name the iterations when you genuinely need to compare two, and treat a missing file as the failure signal — there is never an older image at the path to mistake for output. A directory ( tmp/ as OUT) is the don't care case and gets a generated timestamped name inside it, printed on the saved snapshot: line. Grammar: cadgen dxf snapshot TARGET [OUT] [flags] . Flags: mode view list , camera , theme , size profile , width / height , job , view labels , debug , json . Theme settings live under one theme , mirroring the viewer's Theme tab; the default theme is snapshot , Workbench Light without the ground grid, origin axis or shadows. The command has no display , and no selector, kinematics, section or exploded options at all — they are absent from help rather than refused at runtime, because a drawing carries no CAD topology and display settings are CAD topology settings. No CLI inspects an existing .dxf . For entity/layer checks read it with ezdxf directly (it arrives with build123d), and validate dxf file for the drawing checks; review geometry visually with $cad viewer . Workflow 1. Convert the request into a short brief: outline dimensions, holes and slots, layers, units, output path, and validation targets. 2. Pick the workflow: drafted from scratch, flat pattern of a generated model (create and validate the 3D geometry with $cad first), or flat pattern of an imported STEP. 3. Write or edit the <name .py source with meaningful dimensions as named constants, reusing the model's geometry helpers instead of duplicating formulas. 4. Run each drawing script directly ( python <drawing .py ); do not sweep directories. 5. Validate the generated DXF deterministically, then hand off and report. Viewer integration The CAD Viewer catalogs .dxf files only (artifacts, never scripts) and is a static visualization tool: it renders the .dxf that exists on disk (parsing and meshing it itself — 2D line work for dimensioned drawings, a fold able 3D flat pattern for cut layouts) and never runs a script. A drawing with no .dxf yet simply does