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. You will lose the ability to edit and update them using Civil 3D tools. 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: 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.

What Does This Mean for Civil 3D Users? Let’s say you have a Civil 3D 2018 drawing file. Civil 3D is not backward compatible no matter how you save it. Just keep in mind this is only for vanilla AutoCAD (opening AutoCAD or Civil 3D AutoCAD 2018). That said, you can use the “SAVEAS” command to save to a previous format – which will make the drawing file backward compatible. The chart below shows the various DWG formats throughout the years: Essentially, this means that if you save a drawing file in 2018, it will not be compatible with previous 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). What Does 2018 Mean for Vanilla AutoCAD Users? Traditionally, since AutoCAD version 2000, Autodesk has changed its DWG file format after three versions. Is Civil 3D 2018 Backwards Compatible? The short answer is NO, it is not. Vanilla AutoCAD 2018, however, is backwards compatible. Let’s take a look at how compatible Civil 3D 2018 is with previous versions.

By Rob Bigelow, Infrastructure Industry Specialist, ATG USAĪs with every version of 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.

Civil 3d 2018