Anyone who has ever attempted a data migration knows that there is no such thing as ‘a smooth transfer of power’, as it were. From learning both the legacy system and the new system, business processes, data clean-up, data mapping, deciding between existing tools and creating new ones, there is a lot to keep track of to ensure that what you have at the end matches what you started with.

Migrating CAD engineering drawings poses its own set of unique challenges. AutoCAD and MicroStation drawings can internally have references to other drawing files that exist within the cms (or content management system). When moving these files over to a new system, care must be taken to ensure these references are maintained.

Sword CADtop is a tool that provides users access to CAD drawings that are stored in a Documentum repository directly from within AutoCAD or MicroStation. It gives the user the ability to check in/out drawings, browse, search, view documents and attach reference drawings that exist in the docbase. CADtop maintains reference information by updating the links within the drawing and storing this information in a registered table.

CADtop also provides an import tool that can be used to migrate documents into the Documentum system. It handles importing of documents of multiple types, such as .pdfs, .docs, .tifs, etc. along with the drawing formats, .dwg and .dgn. It is a very simple to use command line tool, but it has its limitations. It can only handle importing up to around 5000 files at a time. However, this can be overcome by creating a batch script to automate the copying of sets of files to a temporary directory and running the import tool.

The import tool uses an XML configuration file to determine the object type, folder path to import from and cabinet/folder to import to. However, those are the only properties you can set. The import tool has no way to attach meta-data from a database to content files being imported. A way around this is to make sure each file has a unique name, then import the files, then using a DFC script, update the properties of all the objects in the docbase from an XML file (for example). This works well as long as all the filenames are unique in the first place, or not drawings with references. If filenames are not unique, then you would have to rename the files, which means the filenames will no longer match the drawing’s internal reference links.

The import tool provides you with a switch that lets you run it in attach reference mode. This allows you to pass an Excel file which consists of a table of parent object IDs, child object IDs and reference filenames, so that you can resolve references within drawing files after they’ve been imported into the docbase. Thereby allowing you to use a tool such as Caliente (Shameless Plug™) to import the drawings into Documentum and update the properties. Then create the Excel file with all the references and run the CADtop import tool to attach them.

The end result will be that when you open one of these drawings through AutoCAD, CADtop will automatically pull out all the references from the Documentum repository and display them, just as in the legacy system.