Hand off DXF to subcontractors

A subcontractor doesn't need your whole model — they need their own trade plus the building outline, in the right units, in a DXF version their CAD can open.

4 min read · Level: intermediate

Quick answer

  • Send each trade two layers: their own discipline and the building outline (A) as reference.
  • Export via File → Export → Per-discipline ZIP or as a single DXF with the layer schema the receiver expects.
  • Keep units on mm and pick R2013 when their AutoCAD is older than 2018. Have the receiver re-measure one known dimension.

Which layers to send

Send each trade exactly two things: their own discipline layer and the building outline (A) as reference. The six NLCS layers are A (building), E (electrical), S (sanitary), M (mechanical/HVAC), D (roof), G (ground/foundation). More than that distracts; less makes the drawing useless on site.

So the sanitary contractor gets A + S, the electrician A + E. How you assign components to layers — and how Diaz remembers that choice per component type — is covered in Discipline layers in 2D. If your drawing came from an architect DXF with its own layer naming, run Tools → Re-map layers first.

Scale and units

A DXF carries geometry in model units, and the unit is declared in the $INSUNITS header — 4=mm, 1=inch. Diaz exports in mm by default. If the drawing arrives 25.4× too big or too small at the receiver, that is a unit mismatch, not a scale problem: re-export with the correct unit. Never re-scale geometry to compensate — it loses accuracy on every subsequent edit.

Step-by-step

  1. Get your layers in order first — every component on its NLCS discipline layer (see Discipline layers in 2D for the assignment workflow). For the hand-off, what counts is the result: each trade layer complete.
  2. Check per trade what will land in their file: toggle visibility in the Layer panel (shortcut L) and confirm their layer plus A tell the whole story. Run Tools → Clash detect before anything leaves the door.
  3. Choose the export route. All trades at once: File → Export → Per-discipline ZIP (one DXF + PDF per trade, A-layer included). One trade: File → Export → DXF and pick the layer schema they expect — keep NLCS, or AutoCAD AIA.
  4. Pick the DXF version: R2018 is the default, R2013 when their AutoCAD is older. Confirm export units — mm is the default; the receiving CAD reads the unit from the $INSUNITS header.
  5. Verify on the receiving side: have them measure one known wall and check text and dimensions — those are the most common round-trip issues.

What goes wrong

  • An empty drawing on their side: two causes — the trade layer never got components assigned, or the A-reference was toggled off at export. Check both before it goes out.
  • Everything 25.4× too big or too small: unit mismatch (mm vs inch). Re-export with the correct unit — never re-scale the geometry.
  • Garbled layer names (é, ü, ñ): an encoding mismatch between UTF-8 and cp1252 — the same pitfall documented on the import side in Import + export DXF.
  • Exploded blocks don't round-trip: if you exploded an imported block, the link back to the original block reference is gone — the architect's file won't reconnect.
  • They ask for DWG: Diaz writes DXF, not DWG. DXF is the industry-standard exchange format and AutoCAD and BricsCAD open it directly — the same programs you use in the other direction to convert an architect's DWG to DXF.

Related

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