A Report Definition is a way to extract and present data from a DGN file in tabular format. The result of evaluating a report definition is a Report, which is a list of data rows. For example, if you want to know how many pipes with a diameter greater than or equal to 5 exist in a model, you can create a report based on the Pipe item type, filtered by Diameter >= 5. When you evaluate the report definition, you get a report in which each row represents a pipe. Reports can also join related sets of properties into a single row. For example, design file properties and WorkSet properties, or item properties and properties of an element to which the item is attached can be listed together in a report. You can also define sorting and formatting options to customize the appearance of the report.

A report can be placed into a DGN model as a table as well as exported to an Excel workbook or .csv files.

You can also upgrade the old tag reports as report definitions.