MicroStation enables you to display redline files.

Redline files are reference attachments created with Bentley Redline. The configuration variable RDL_DIR specifies the directory location(s), root filename(s), and extension(s) for redline files. By default, any redline file that meets the following criteria is automatically attached to the model to which it was originally attached in Bentley Redline when that model is activated in MicroStation:

• The redline file is located in the same directory as the open DGN or DWG file.
• The redline file has the extension ".rdl."
• The redline file's name is identical to that of the open DGN or DWG file or matches the name of the open file but contains additional characters.

For example, if the redline files Graphics Display.rdl and Graphics Display2.rdl were created in Bentley Redline as attachments to the model "Index" and stored in the same directory as Graphics Display.dgn, they would be automatically attached when that model is activated in MicroStation.

If a redline file is attached to a model in the open DGN file, it is automatically detached when the model is deactivated.