Civil 3D 2008 and File Formats

I heard a lot of questions being asked today during the webcast about file format.  My information here may not be written in “Official” terminology, but it will explain what kind of behavior you can expect from opening drawings back and forth between 2007 and 2008.


AutoCAD 2004,2005, and 2006 had the same drawing format- the 2004 dwg.  This meant that if you had any of these three releases you could open drawings created in any of the other releases.

AutoCAD 2007 brought with it a new file format- the 2007 dwg.  You could open 2004 format (and below) in AutoCAD 2007, but 2007 dwgs could not be opened in anything but 2007.

AutoCAD 2008 also works with the 2007 dwg format.  So if you work with people who use 2007, you will be able to share drawings back and forth with no necessary conversion.


Civil 3D is built on AutoCAD.  So all of the above information applies to the AutoCAD objects you create in Civil 3D.  Such as: lines, arcs, circles, dtext, vports, dimensions, etc. etc. etc.  This means that if all I ever did in Civil 3D was “draw” using AutoCAD tools, I could share drawings between 2008 and 2007 with no problem.

However, the Civil 3D objects don’t follow these rules.  Every release, Civil 3D objects become smarter, faster and more powerful.  So from a Civil 3D object perspective, each release is a whole new “format”.

What this means in practice is that…

You can open a Civil 3D 2007 (or lower) drawing in Civil 3D 2008 and it will bring all of your old objects forward and they should (should) be OK.  There are some things you’ll want to do (like convert your subassemblies to .NET and do an audit, etc) but for the most part I haven’t seen anything fundamentally messed up. (I make no guarantees, however.)

You can open a Civil 3D 2008 drawing in Civil 3D 2007 but any Civil 3D objects are absolutley unusable, and probably unviewable, too.  Most often they show up as big rectangles.

If you have a drawing in Civil 3D 2008 that you need someone using an AutoCAD 2007 or lower based program to be able to see, you must either explode everything and save, or do a File>Export to AutoCAD (2007, 2004, etc).

The moral of the story:

If you want Civil 3D 2008 objects to remain intellegent and useable, they must remain in Civil 3D 2008.  Going backwards in any form will make them “dead”.


  1. governa says:

    One clarification. If you save the 2008 Civil 3D drawing with Proxy graphics turned on, then all will display properly in 2007, they are just read only object, and can’t be edited anymore. The one exception will be with new objects, say the View Frames from Plans Production which is new to 2008, where you might not get the object.

    I just tried it though and everything displayed fine, but then I have both 2007 & 2008 on the same machine.


  2. Ah ok. That throws some additional confusion into the mix then. With proxy graphics on, you could save the drawing, do AutoCAD type edits in 2007 and then come back into Civil 3D 2008 with no problem. (Except of course for the new objects). Though that is not a workflow I would probably recommend. What happens to those new objects when you open back in 2008?

  3. Matt Kolberg says:

    In my experience the new 2008 objects round trip nicely. Meaning there seems to be no issue saving to 2007, editing with 2007 then reopening with 2008 and finishing up.


  4. Tim Shoemaker says:

    All fine and dandy. But Autodesk has taken the time to disable your ability to create new Civil 3d 2007 objects in a drawing if it has been used by 2008. Is it my imagination or is this just another way to force everyone to stay on the Pay Them to Test Their Software, I mean subscription program.

  5. Naleenda Chamara says:

    I have a drawing , It is a civil 3D 2008 version. I want to open and edit it using civil 3D 2007 version. I can open but can’t edit. Can you please say what to do