What Civil Engineers Should Know About Sharing DWG Files with Other Firms

You finish a drawing, it looks perfect on your screen, and you email the DWG to the architect or the surveyor you are teaming with. An hour later, the phone rings. “Your xrefs are missing.” But it was all there when you sent it.

Here is the short version. A DWG leans on other files, like xrefs, images, and fonts. Send the main file alone, and those links break. Ask what software and release the other firm runs. Then send the full set with eTransmit. For Civil 3D, plan for data shortcuts too.

A DWG is rarely alone

The drawing you see on your screen is usually not one file. It is a main drawing plus a whole supporting cast that loads in behind it.

Those supporting files are called external references, or xrefs. Your drawing might reference the survey base, the architect’s floor plan, an aerial image, and a title block, each one a separate file living somewhere on your network. On top of that, your drawing relies on fonts, plot styles (the rulebook that controls how it prints), and other support files.

So when you “send the drawing,” you are often sending one piece of a set that needs several other pieces to look right. Send just the one piece, and the rest is missing on the other end.

Why it breaks on their end

Each xref is remembered by its file path, the address that tells AutoCAD where to find it.

The problem is that those paths usually point to your folders. Something like a drive and folder that only exists on your computer or your network. When the other firm opens your drawing on their computer, AutoCAD goes looking for the survey at that exact address, does not find it there, and reports “xref not found.” The reference is not gone. AutoCAD just cannot find it at an address that does not exist on their machine.

For example: your survey base lives at a path on your office server. You send only the main sheet. The other firm opens it, and AutoCAD tries to load the survey from your server path, which their computer cannot reach. So the survey vanishes from the drawing. Nothing is corrupt. The map just points to your house.

Nothing is corrupt. The map just points to your house.

The fix: send it with eTransmit

AutoCAD and Civil 3D have a command built for this, called eTransmit. You should use it for every handoff. It packages your drawing with the files it depends on, like xrefs, images, and plot styles. It can build one zip file or a plain folder. It also sets the paths so the references find their files in the package. Fonts are a separate option in the setup, so check that box. TrueType fonts belong to their makers, so the other firm may need its own copy. If a font is missing, AutoCAD swaps in a substitute.

Instead of emailing one DWG and hoping, you run eTransmit. It gathers the set for you. The other firm unzips it and opens the drawing. The xrefs load, because the links point to files that are in the package.

This is the biggest fix in this post. Do not just attach a DWG. Send a package made with eTransmit.

Two more settings help. If the other firm only needs your drawing for reference, eTransmit can bind the xrefs into the drawing. Then nothing can come loose. Arkance, an Autodesk reseller, also suggests setting the plotter to “None” and purging the drawing first. That heads off printer errors and trims file size.

Relative paths vs. absolute paths

One setting prevents the problem at the source. It is how your xref paths are stored.

An absolute path is the full address to the file. It only works on the machine where that exact route exists. So it breaks when the drawing moves. A relative path describes where the xref sits in relation to the main drawing, like “in the xrefs folder next to me.” That kind of path survives the move. As long as you keep the files in the same arrangement, the relationship holds wherever the folder lands.

For project xrefs, relative paths are the safer default. Keep your project files in a consistent folder structure too. Then your references travel well, and eTransmit has an easy job. There is one limit. Autodesk says a relative path is not available when the xref sits on a different drive or server. Shared title blocks on a standards drive are a common case. A full path can be fine for files like that, since they rarely move.

Civil 3D’s extra wrinkle: data shortcuts

Civil engineers have one more thing to watch, because Civil 3D adds a layer that plain AutoCAD does not. Your surfaces, alignments, and pipe networks are often shared between drawings using data shortcuts. A data shortcut is a reference to a design object that lives in another source drawing.

So a sheet might show a surface that does not live in that sheet. It lives in a source drawing and is referenced in. Send the sheet without the source, and the reference breaks. This break is sneakier than a missing xref. The sheet keeps a cached copy of the object, so the surface may still show. But it can’t update, and it may be out of date. Check that the source drawings made it into the package.

The practical move depends on the job. If the other firm needs to work with your live surfaces and alignments, you may need to send the whole project structure, or coordinate your data shortcut setup with them. If they just need to see and reference the result, exporting to a plain DWG that “bakes in” the geometry can be cleaner. Autodesk notes this turns Civil 3D objects into plain lines and shapes, so the design data does not come along. Either way, a Civil 3D handoff is worth a second of thought.

The software release matters too. Autodesk says Civil 3D objects do not work in older Civil 3D releases. Open your drawing in an older release, and those objects show as proxy objects that can’t be edited. A firm with plain AutoCAD needs Autodesk’s Object Enabler to see them properly. Without it, they may see flat graphics or empty boxes. So ask what software and release they run before you send. For more on keeping Civil 3D projects healthy, see our post on why Civil 3D projects run slow.

A clean handoff checklist

Pull it together into a routine that makes you the firm everyone likes to share files with.

First, ask the same question we always start with: does the other firm need to view the drawing or edit it? If they just need to see and mark it up, a PDF is the simplest, safest answer, as we cover in our post on sharing large CAD files with clients. If they need the editable files, ask what software and release they run. Then keep going.

Then, use eTransmit to package the full set, not just the main DWG. Check the fonts option, and bind the xrefs if they only need a reference copy. Keep your xrefs on relative paths and your folders organized so the references travel cleanly. For Civil 3D, decide how to handle your data shortcut sources, and include what they need. And tell them what is inside: a quick note listing the files, the coordinate system, and anything they should know. That little note saves a long phone call.

Do that, and your drawings are far more likely to open complete on the other end. A quick call to confirm it opened is still worth it.

Frequently asked questions

Why do my xrefs disappear when another firm opens my drawing?

Because the xref paths point to folders on your computer that do not exist on theirs. AutoCAD looks for the referenced files at your addresses, cannot find them, and reports them as missing. The references are not gone; they are just pointed at a location the other firm cannot reach.

What is eTransmit and why should I use it?

eTransmit is an AutoCAD and Civil 3D command that packages your drawing with its xrefs, images, and plot styles. Fonts are an option you turn on. It sets the paths to point at files in the package. It is the best way to send a full drawing set to another firm.

What is the difference between a relative and absolute xref path?

An absolute path is the full address to a file and only works on the machine where that route exists, so it breaks when the drawing moves. A relative path describes where the xref sits in relation to the main drawing, so it survives being moved as long as the files keep their arrangement. Use relative paths for project xrefs when you can. They are not available when the xref sits on a different drive or server.

How is sharing a Civil 3D file different from a plain AutoCAD file?

Civil 3D often shares surfaces and alignments through data shortcuts, which reference design objects in other source drawings. Send a sheet without its source and those references break. A Civil 3D handoff needs extra care to include the right source data, or to export geometry to a plain DWG. Civil 3D objects also do not work in older Civil 3D releases, so ask what release the other firm runs.

We will make your file handoffs painless

Sending and receiving drawings between firms should be smooth, not a source of broken xrefs and embarrassing phone calls. Our managed IT services keep the file side of this running for small engineering firms. That means a clean folder structure on your server or cloud, solid backups, and the computers your team works on. Your CAD lead owns the path and handoff habits. We keep the storage behind them steady. Based in East Tennessee. Serving firms nationwide.

If sharing files with other firms keeps causing trouble, give us a call for a free IT checkup. We will look at where your project files live and how they are backed up. Then your team can focus on the engineering, not the technology.

Sources: Modify Transmittal Setup Dialog Box (Autodesk); About Setting Paths to Referenced Drawings (Autodesk); Civil 3D Drawing Compatibility (Autodesk); About Data Sharing Methods (Autodesk Civil 3D); Repairing data shortcuts and data references (WisDOT); AutoCAD: Working with Xrefs, Use eTransmit (Arkance)