dxf

DXF import and export

"DXF" in QET means two unrelated features that happen to share a file format:

	Direction	Where	How
Export	sheet → .dxf	File → Export, alongside PDF/PNG/SVG	in-process, QET's own code
Import	.dxf → element geometry	the element editor's Import a DXF file	shells out to a separate third-party program

They don't round-trip each other and aren't part of the same code path. If you're looking for "import a DXF drawing as a sheet", that isn't what either of these does — see §3.

Source: sources/createdxf.{cpp,h}, sources/dxfpaintdevice.{cpp,h}, sources/dxfexport.{cpp,h}, sources/dxf/dxftoelmt.{cpp,h}.

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1. Exporting a sheet to DXF

File → Export, same dialog as PDF/PNG/SVG, one .dxf file per sheet. The border, title block and every diagram item on that sheet are included.

It also runs from the command line, like the PDF, PNG and SVG exports.

From the command line: --export-dxf

qelectrotech --export-dxf myproject.qet out/
qelectrotech --export-dxf myproject.qet out/ --show-terminals
qelectrotech --export-dxf myproject.qet out/ --dxf-blocks
qelectrotech --export-dxf myproject.qet out/ --dxf-attributes

• One file per sheet, named like the PNG and SVG exports: the sheet number on two digits, then its title — 01_General.dxf, 02_Macro 3.dxf. The output folder is created if it does not exist.
• The same file the Export dialog writes, with the dialog's default options, which come from the export settings in the preferences (border, title block and so on). Given the same settings, the two are byte-identical. The column numbers across the top border follow the preference that starts them at 0 or 1, so a machine with a different setting gives a different border.
• --show-terminals draws the terminals, as the dialog's option does.
• --dxf-blocks writes each symbol as a DXF block, and --dxf-attributes also turns the symbols' texts into block attributes; see Symbols as blocks below. --dxf-attributes on its own implies --dxf-blocks. Without either flag, the two options keep the value saved in the preferences (both off unless you changed them).
• Pictures become outline boxes, as in the dialog (see below), and a note is printed saying so.
• Scripts run with --run get the same export as qet.exportDxf(outDir, showTerminals) — see JavaScript Scripting.

Exit codes are the same as the other exports: 0 success, 1 the export failed (for example, the output folder cannot be written), 2 called wrongly.

Two exports of the same sheet give identical files, so a DXF can be compared with an earlier one to see what changed. (Before PR #1075, every export wrote its entities in a different order.)

Layers

Each kind of content goes on its own layer, so a CAD program can tell the border from the wires. (Before PR #1079, everything sat on layer 0.)

Layer	What is on it
QET_BORDER	the sheet frame, with its column and row headers
QET_TITLEBLOCK	the title block
QET_SYMBOLS	the drawing of each symbol
QET_SYMBOL_TEXTS	texts belonging to symbols: labels and the like
QET_TERMINALS	terminal markers, only when terminals are drawn (--show-terminals or the dialog option)
QET_WIRES	the wires
QET_WIRE_NUMBERS	the texts on wires
QET_JUNCTIONS	junction dots
QET_TEXTS	free texts
QET_XREFS	cross-references: contact tables beside a master, labels beside a slave
QET_SHAPES	lines, rectangles, ellipses and polygons drawn on the sheet
QET_TABLES	tables such as the parts list
QET_IMAGES	the outline boxes that stand in for pictures

The names are fixed and English, whatever language QElectroTech runs in, so a CAD user's layer filters and scripts keep working. The QET_ prefix keeps them together in the layer list and apart from the receiving drawing's own layers.

2612_ats_singlephase.qet, sheet 1, exported with this change and rendered with ezdxf. Only layer settings in the viewer differ between the three.

Colours. Where QElectroTech sets no colour of its own, entities take their layer's colour (BYLAYER), so recolouring a layer in the CAD program recolours everything on it. The file still looks the same when opened, since every layer starts white on black, black on white. Wires keep the colour they have on the sheet: until this change every wire was exported in the default colour, and 723 of the 3,190 wires in the example projects lost theirs. A two-colour wire gets its main colour.

What does not change: the lines themselves, their positions and the DXF version. Only the layer each entity is on and its colour code differ from an older export.

Not included yet: an option to put everything back on layer 0, and dashed wires (they come out continuous).

Symbols as blocks

By default every symbol is exported as loose lines, arcs and texts: in a CAD program, selecting a contactor means picking each of its lines. Two options in the export dialog change that. Both are off by default, and with both off the file is the same as before they existed.

Option in Fichier → Exporter (File → Export), format DXF	Command line	Effect
DXF : symboles en blocs (DXF: symbols as blocks)	--dxf-blocks	each symbol becomes one DXF block, placed with an INSERT
DXF : textes des symboles en attributs (DXF: symbol texts as attributes)	--dxf-attributes	the symbol's own texts become attributes of its block. Can only be ticked when the first option is

The two labels are not translated yet, so the English interface shows them in French as above. They are in the Options de rendu (Rendering options) box of the export dialog, and on the Export page of the preferences, where they set the default for the dialog and for --export-dxf.

Symbols as blocks. Each symbol definition a sheet uses is written once, as a block, and every placed symbol is an INSERT of that block, carrying only its position and its quarter-turn. A CAD program then selects, moves, counts and replaces a symbol as one object, and its block list shows which symbols the sheet uses.

• Block names come from the symbol's file name, in capitals, with QET_ in front: contacteur.elmt gives QET_CONTACTEUR. Characters DXF does not allow in a name become _, names are cut at 31 characters, and two different symbols that end up with the same name get _2, _3… Repeat exports give the same names, so two exports of an unchanged sheet are still identical.
• The lines inside a block keep their layers (QET_SYMBOLS, QET_SYMBOL_TEXTS, QET_TERMINALS), so the layer switches above still work.
• Wires, free texts, cross-references and everything else stay as before: only symbols become blocks.

Texts as attributes. With the second option, the texts a symbol carries on the sheet — its label, function, comment and so on — are written as attributes of its INSERT instead of loose TEXTs. A CAD program moves them with the symbol and can list or edit them (in AutoCAD, ATTEDIT or attribute extraction). Each attribute is written exactly where, and as, the text was on the sheet.

Text on the symbol	Attribute tag
shows an information field	the field's name in capitals: LABEL, FUNCTION, COMMENT…
typed text	TEXT1, TEXT2…
second line of a two-line text	the tag with _2 added

LibreCAD does not show attributes. Opened in LibreCAD (checked with 2.2.1.5), a file exported with this option shows the symbols without their labels. That is why it is a separate option: leave it off if the drawing is going to LibreCAD. AutoCAD shows them.

Part data as hidden attributes. Whenever symbols are exported as blocks, every information field of a symbol that has a value — label, manufacturer, manufacturer reference, supplier, quantity and the rest — is also added to its INSERT as a hidden attribute, tagged with the field's name in capitals (MANUFACTURER, MANUFACTURER_REFERENCE…, cut at 31 characters). Hidden attributes change nothing on screen in any reader, but a CAD program can list them, for example with AutoCAD's attribute extraction, to build a parts list from the drawing. A field already written as a visible attribute is not repeated, and the label formula is left out: it is how the label is made, not part data.

How it's rendered

Rather than a separate DXF-specific drawing pass, QET reuses the exact same paint() code every element and shape already has for screen/PDF/PNG rendering. A custom QPaintEngine (DxfPaintEngine) sits behind a QPainter, intercepts the small set of drawing calls those paint() methods actually make, and translates each into a DXF entity instead of pixels. That's a deliberate design choice: an item's rendering code is "already correct" for every other export, so DXF export can't drift out of sync with what you see on screen — it draws the same calls, just recorded differently.

What that costs — real fidelity limits

The DXF dialect targeted (AC1006) and the deliberately narrow set of translated calls mean some things don't come across:

QET drawing call	DXF result
Lines	LINE
Rectangles	POLYLINE outline — no fill, even if the rectangle is filled on screen (this DXF dialect has no filled-rectangle primitive)
Circles	one exact CIRCLE
Arcs of a circle	one exact ARC
Ellipses and arcs of an ellipse	a POLYLINE through the curve, one point every 5 degrees: this DXF version has no ellipse entity
Polygons	POLYLINE
Text	TEXT
Filled paths	outline only, same as rectangles — no HATCH
Images / pixmaps	not exported. DXF has no raster-image entity in this dialect; a placeholder rectangle is drawn in the image's position, size and rotation instead, so layout is preserved but the picture itself is not

Anything outside this list (gradients and similar) is not silently dropped — it logs a warning, on the principle that a caller should find out immediately that something wasn't exportable rather than get a DXF file quietly missing content.

If your drawing relies on filled shapes, hatching, or embedded images surviving into DXF, they won't — plan around outlines and text.

Circles, scale and the title block on the right were fixed in PR #1350 (merged 7 October 2026). Before it, every circle and arc came out as a flattened diamond made of four arcs; the drawing was scaled differently across and down, so round things came out oval; and a title block placed at the right of the sheet was squashed into the top corner. Now one scale is used for both directions (the largest that fits the sheet), circles and arcs are exact, and a title block on the right is laid out as on screen, turned a quarter. A DXF exported with an older build is worth exporting again.

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2. Importing a DXF into an element

This is a symbol-authoring tool, found in the element editor (File → Import a DXF file), not the diagram/sheet editor. It reads geometry out of a .dxf and adds it as drawing primitives to the element you currently have open — a way to trace or reuse CAD line art when drawing a new symbol, not a way to bring a DXF schematic into a project.

It needs a separate program

Unlike export, import is not built into QET. It shells out to dxf2elmt, a third-party console tool (Vadoola/dxf2elmt) that QET looks for next to itself (<data dir>/binary/dxf2elmt, or .exe on Windows). If it isn't found, QET shows a dialog with the download link and the folder to unzip it into, rather than failing silently — the same pattern as qet_tb_generator for terminal block generation (see Automating QElectroTech).

QET runs it as dxf2elmt <file> -v, reads its stdout as the resulting .elmt XML, and pushes it onto the element editor's undo stack as one operation. On a large DXF, a warning dialog tells you the import may take a while before it starts.

Since dxf2elmt is a separate project, its own interpretation of DXF entities — what maps to what, and its own limitations — lives with that project, not with QET.

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3. What neither of these is

• Not a way to place a DXF drawing on a sheet as-is. Import only feeds the element editor.
• Not round-trip safe. Export's outline-only, no-image limitations (§1) mean a .dxf written by QET is not a faithful source to import back, even setting aside that import and export use entirely different code.
• Not a general CAD interchange path. Export puts content on named layers and can write symbols as blocks with their texts and part data as attributes (§1), but wires, cross-references and the rest stay plain geometry, and import works at the level of individual drawing primitives.

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See also: Automating QElectroTech · CLI Reference · Linking elements