Autodesk AutoCAD Civil 3D Reader

Licensing options for this format begin with FME Desktop Professional Edition.

The AutoCAD® Civil 3D Reader module allows FME to read data used by Autodesk® Civil 3D and compatible systems. AutoCAD drawing files consist of drawing settings and configuration, as well as a series of entities, or graphic elements, organized into layers.

AutoCAD drawing files used by Autodesk Civil 3D extend the entities and configuration of CAD drawing, enabling them to contain objects useful for Architecture Engineering and Construction (AEC).

Overview

FME provides broad support for many AutoCAD and entity types and options and for reading and writing AutoCAD file versions up to and including 2019, as described in the Autodesk AutoCAD DWG/DXF Reader/Writer format documentation.

  • Drawing files created with version 2007 – 2009 of Autodesk Civil 3D (commonly referenced as just version 2007 files) are supported.
  • Drawing files created with version 2010 – 2012 of Autodesk Civil 3D (commonly referenced as just version 2010 files), and version 2014 of Autodesk Civil 3D are supported as of FME 2014; however Alignment Superelevation sub-entities are not yet supported.

The AutoCAD Civil 3D Reader is additionally capable of reading AEC information from these drawing files; however, there are different version requirements.

More specifically, AEC information could be categorized into data, data relationship information, settings, and project information. Of these, only data and some data relationship information is supported by the AutoCAD Civil 3D Reader. This AEC data may further be categorized into objects, labels, and styles. Of these, only objects are supported by the AutoCAD Civil 3D Reader. The particular objects supported are listed in Feature Representation.

Background

For background information on AutoCAD drawing files and their contents, please refer to the Autodesk AutoCAD DWG/DXF Reader/Writer format documentation.

Supported Versions

FME 2021.n supports reading Civil 3D DWG files created by Civil 3D 2021 or earlier software.

Here is a list of the different forms of Civil 3D data files, and what can be done with them:

  • FME can read files created in Civil 3D 2021 or earlier civil 3D applications.
  • Data exported from newer versions of Civil 3D into older Civil 3D files are generally not readable. The conversion process changes the Civil entities into proxy data.
  • Data from newer versions of Civil 3D can be exported to LandXML, then imported using older versions of Civil 3D. From there the older Civil 3D application can save an older version Civil 3D DWG file which FME can read.
  • Civil3D entities in newer versions of Civil 3D can be exported to SDF so you can use the SDF reader in FME to read them (regular DWG entities can be read with the ACAD reader).

The recommendation is to ensure that the Civil 3D data that is to be worked with, is of a version that is native to the application which created it. Otherwise, data may appear to be in the correct version, but in fact it may have undergone a conversion process which has removed some desired data.

Supported Geometries

For FME 2021.n reading from Civil 3D Version 2021 or earlier Civil 3D DWG files.

Supported:

  • Civil 3D data (some, see below)
  • Civil 3D data relationships (some, limited to ID references)

Unsupported:

  • Civil 3D project
  • Civil 3D settings

Supported:

  • Objects (some, see below)
  • Parcel Segment Labels

Unsupported:

  • Most Labels
  • Styles

Supported:

  • Alignments
  • Parcels (and related User Defined Properties)
  • Pipes (and related User Data Fields)
  • Pipe networks
  • Pressure pipes
  • Pressure pipe networks
  • Point groups
  • Points (and related User Data Fields)
  • Structures (and related User Data Fields)
  • Appurtenances
  • Fittings

Unsupported:

  • Assemblies
  • Corridors
  • Feature lines
  • Gradings
  • Mass haul views
  • Match lines
  • Profile views
  • Profiles
  • Sample lines
  • Sections
  • Section views
  • Subassemblies
  • Surfaces
  • Survey figures
  • Survey networks
  • View frames

Workbench Reader Dataset

The value for the Reader Dataset is the path to a DWG/DXF File(s).

Reader Overview

The AutoCAD reader first reads the header and table information from the drawing file being processed, and caches information on blocks, shape files, layers, linetypes, and applications. These cached values are referenced by entities throughout the file and are needed when processing the entities.

The reader then extracts entities, one at a time, from the entity section of the drawing file and passes them on to the rest of the FME for processing. Complex entities such as polylines and inserts are extracted as single FME features. If the entity has attribution stored as extended entity data, then this is also read and placed in the feature.

When the AutoCAD reader encounters an entity type it does not know how to process, it simply sets the entity type of the feature and returns it. This feature is then logged by the FME correlation subsystem and the reader moves on to the next entity.

Esri Product Coordinate System Information

To specify the FME coordinate system, the FME AutoCAD reader can recognize a coordinate system associated with AutoCAD data by Esri products.

The AutoCAD reader will first look for the following files in the source folder:

  • <filename>.prj
  • esri_cad.prj

If neither of these files is present, the AutoCAD reader will try to find an ESRI_PRJ entry embedded in the file.