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Translating Data with Civil 3D, Part 2 (CAD Clinic: Civil 3D Tutorial)

31 Jan, 2007 By: Mike Choquette

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More in LandXML and other data transfer techniques.

Although Civil 3D 2007 contains new Survey functionality, many Civil 3D users are still required to exchange data with outside consultants for surveying and design services, as well as to collaborate with other offices on shared projects. Many companies also have legacy project data they would like to bring forward into Civil 3D. At present, Civil 3D has many options for translating data between other civil/survey applications, as well as from one file server or Vault project to another. This is the second installment on this topic; the series began in the January 2007 Cad Clinic column. Last month we explained what LandXML is and described the Import and Export LandXML commands available from the File pull-down menu. These commands are very useful when transferring civil and survey data into or out of Civil 3D. This column looks at other ways to import and export data into and out of Civil 3D 2007.

Importing and Exporting LandXML Data into and out of a Survey Database
The Survey Toolspace provides a separate Import LandXML command with options that relate to Survey functions, such as choosing an equipment database and figure prefix library. You can locate this command by right-clicking on the name of the Survey Database in the Survey Toolspace. Note there is also an Export LandXML command available in this context menu.

Besides LandXML data files you can also transfer civil/survey data with these commands:

Projects / Extract Civil 3D Data (within Land Desktop). This command scans for Civil 3D objects in the current drawing and makes them available to be added to the current Land Desktop project database. Note that some Civil 3D data, such as corridor models, cannot be translated (but corridor surfaces can).

File / Import / Data from Land Desktop (within Civil 3D). This command is very similar to importing a LandXML data file. Instead of being prompted to select a LandXML file, though, the user is asked to browse for a Land Desktop project folder. Once you choose one, that project's Land Desktop project data becomes available for import into Civil 3D. Note that some Land Desktop data, such as design control settings and roadway templates, cannot be translated. One drawback to this command (compared to exporting and importing LandXML) is that it doesn't transfer points or point groups.

EXPORTLDTDATA (within Civil 3D). This undocumented command is not available from the pull-down menus, nor is it listed in the Help system. It may save you some trouble, though, if you ever need to send Civil 3D data back to a Land Desktop project. After typing in EXPORTLDTDATA at the Command line in Civil 3D, the program prompts you to select data to be translated and a Land Desktop project to export to. Following this export (or import, depending on which side you're on) the data is available for use inside that project's Land Desktop drawings. There is one trick to this, though: the command only works after you launch the File / Import / Data from Land Desktop command once in your current session. After the dialog initializes you are free to cancel the Import command and then launch EXPORTLDTDATA. This command can translate points back to Land Desktop, but not Point Groups. EXPORTLDTDATA will overwrite and replace any existing data of the same point number or object name, so be careful!

Survey Data
As of this writing, survey data can be imported into Civil 3D through LandXML and Autodesk FBK files (the same fieldbook format used by Land Desktop). Survey data can also be manually entered through the Survey Toolspace and through the Survey Command Line in Civil 3D. Civil 3D 2007 does not contain a utility that allows for direct connection to data collectors, but several supplemental tools including the Trimble Link, Carlson Connect, and Leica X-Change do allow for direct connections and the creation of FBK files. You can find links to these packages at this site:

Bits 'n' Pieces
There is also a handful of other import and export commands sprinkled around Civil 3D relating to points and surfaces, including:

• Import points. The Points / Create Points / Import Points command creates point objects based on the data stored in an external point file or database. The command lets you work with a number of industry-standard formats such as PNEZD (point-northing-easting-elevation-description format) for comma- and space-delimited files. Note the External Project Point Database format lets you import the points contained in a Land Desktop project database (project folder/COGO/Point.mdb), though it doesn't carry across point groups.
• Export Points. The Points / Utilities / Export Points command allows you create a point file through a similar dialog used in the import Points command.
• Surfaces. Land Desktop surfaces can be imported into Civil 3D directly through Surfaces / Import TIN. You are prompted to browse for a .TIN file located within the DTM subfolder of the desired Land Desktop project.
• Surface Breaklines. You can include surface breaklines defined in an external ASCII FLT file if you wish. The surface can maintain a reference to this file afterwards if desired. Find instructions on how to craft these files in the Civil 3D User's Guide (the online Help system).

Coming Soon
This is the second installment in a series on data transfer into and out of Civil 3D. This and the preceding article have outlined the importance of transferring Civil and Survey data from one source to another. This article described how to bring LandXML data into and out of survey databases, commands for directly transferring data from Civil 3D to and from a Land Desktop project, and some miscellaneous point and surface import and export commands. In the following and final installment of this topic we will discuss transferring data within, into and out of Vault databases, as well as a strategy for safely transferring drawing files between applications and different versions of the same application.