Why does the format matter at tender?
The drawing that goes out with a quote has two kinds of reader. The client's engineer and the evaluator read it to check fit and compare offers, and a PDF serves them well.
The drafter reads it to put your switchboard, kiosk or enclosure into the site layout. Given only a PDF, they trace the outline from the dimensions, and a dimension misread at that point turns up months later as a clash on site.
What does a DWG carry that a PDF doesn't?
Real geometry at true scale. Layers, blocks with their attributes, and text that is still text. A drafter can insert your GA as a block or an external reference, snap to the corners of the plinth and measure the clearance to their own wall without redrawing anything.
Some of it breaks in transit. A drawing that references other files arrives with blank areas unless those references are bound or sent with it, which is what AutoCAD's eTransmit packages up. Fonts the client doesn't have get substituted, and lineweights depend on the plot style table, so a DWG printed on someone else's machine rarely matches your PDF.
There is also the version. An older release of AutoCAD can't open a file saved in a newer DWG format, so ask which release the client drafts in and save down to it.
When should you send a DXF?
When the client drafts in something other than AutoCAD, or asks for DXF by name. Nearly every CAD program reads it. Lines, arcs and text come across well; what tends to go missing is the information one program attaches to its own objects, such as the symbol and wire number links an electrical add-on keeps, which can arrive as plain geometry.
Open the DXF in a second program before it goes out. Enclosure and switchboard builders keep DXF for another reason too: it is the format most laser and CNC cutting shops take for flat sheet metal profiles.
Which file is the contract record?
Almost always the PDF. It is the file that was evaluated, and the revision and date in its title block are the ones the drawing register records. Nobody can alter it by accident. Native files usually go out marked for information, with a line saying the PDF governs where the two differ. If your terms don't say that, put it in your qualifications.
Keep the revision identical in both. A DWG showing revision C sent next to a PDF at revision B gives the client two versions of your offer, and nobody can say later which one was priced.
What to send with a quote, and what to check first
| File | Who uses it | Check before it goes |
|---|---|---|
| The evaluator, the client's engineer, the contract record | Vector rather than a scan, to scale with a scale bar, revision matching the register | |
| DWG | The client's drafters | Saved to their AutoCAD release, references bound, their title block and layers if they asked |
| DXF | Drafters on other CAD programs, sheet metal shops | Checked in a second program, units set |
| STEP | 3D coordination and clash checks | Outer envelope and connection points only, unless detail was asked for |