Is Civil 3D 2018 Backwards Compatible?

Civil 3D 2018 is here, and it has some great new features built in.

As with every new version, Civil 3D users need to pay close attention to the file format and compatibility so that they don’t accidentally make the file unusable for themselves, or for consultants and clients they are working with. Let’s take a look at how compatible Civil 3D 2018 is with previous versions.

Is Civil 3D 2018 Backwards Compatible?

The short answer is NO, it is not. Vanilla AutoCAD 2018, however, is backwards compatible. Well, sort of.

What Does 2018 Mean for Vanilla AutoCAD Users?

Traditionally, since AutoCAD version 2000, Autodesk has changed its DWG file format after three versions. Since 2013, however, Autodesk decided to keep the same DWG format (AC1027) for 5 versions, until they finally decided to give AutoCAD 2018 a new DWG format (AC1032). The chart below shows the various DWG formats throughout the years:

AutoCAD Version Chart of Various DWG formats

Essentially, this means that if you save a drawing file in 2018, it will not be compatible with previous versions. That said, you can use the “SAVEAS” command to save to a previous format – which will make the drawing file backward compatible.

AutoCAD Save As screenshot with file types showing

Just keep in mind this is only for vanilla AutoCAD (opening AutoCAD or Civil 3D AutoCAD 2018). Civil 3D is not backward compatible no matter how you save it.

Civil 3D AutoCAD 2018 Desktop App Icon

What Does This Mean for Civil 3D Users?

Let’s say you have a Civil 3D 2018 drawing file. You can open that file in Civil 3D 2018 and save it there. As expected, you will be able to use all Civil 3D objects as normal; but if you try to open that drawing file in Civil 3D 2017 (or an earlier version) after saving it in a Civil 3D 2018 you get this message:

This drawing was created with a newer version of Civil 3D.

If you click OK, the Civil 3D objects will be transformed into proxy objects, which basically means profiles, alignments, and surfaces will be more like a block. You will lose the ability to edit and update them using Civil 3D tools.

Why Did This Happen?

Similar to Civil 3D 2017, Autodesk made the decision to update their objects for the 2018 release with custom and AEC objects of vertical and 3rd party products. This will hopefully enable them to implement improvements in the initial release, as well as provide the platform with some new features on the horizon.

How Does This Affect Me?

If you are working on a project in earlier releases, keep the files with those versions until you are ready to move the entire project to the newest version. Just be prepared for when you save a file in the Civil 3D 2018 format; plan on keeping it there.

Rob is a GIS specialist, civil designer, project manager, and CAD manager. He is uniquely skilled in CAD and GIS products, networking, security, database, cloud services, and computer technical support. Rob is a Certified Geographic Information Systems Professional. He understands a customer’s project from the initial conception to the final stages of approval, consistently meeting their needs, budgets and timelines. As a CAD manager, he helps customers achieve their goals of implementing reasonable solutions, more efficient methods, user-friendly standards and procedures, documentation and libraries, cloud storage solutions, and ways to use database objects to their full potential.

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