If the file names contained in the index files do not include file extensions, default extensions can be specified, so that the framework can search for a file with the same name and a default extension in the searched directory.
For example, if a given index file determines the footprint of dgn files a, b and c and that those files are identified in the index strictly as a, b and c, the framework will look for the presence of files a b and c in the searched directory.
If extensions are specified (for example dgn and dwg), the framework will look for the presence of files named a.dgn or a.dwg, b.dgn or b.dwg and finally c.dgn or c.dwg.
If the documents are identified using a file name and a file extension in the index file, then no extensions need to be specified and the framework will search for these file names directly in the searched folder.
More than one extension can be specified, using a comma to separate all file extensions (for example: dgn,dwg,rdl). If more than one extension is specified, the framework will search sequentially the searched folder using each file extension in the order they appear in the dialog. As soon as one matching file is found, it uses its name as the object name in the SLF.
In the case of the dgn,dwg,rdl example, this means that file a.dgn will be searched, then a.dwg and a.rdl. But if a.dgn is found, a.dwg and a.rdl will not be searched.