Design history allows users to better manage the design process. It provides a complete revision control system that allows users to track and view the incremental changes made to a model.

Changes can be tracked down to the element level. To help track the revisions, each is identified with a revision number, file name, date and time, author, description of the change, and tags.

A revision records the difference between the current state of the model and the last revision saved. Only the difference is saved in the design history area of the DGN file, which minimizes additional storage requirements for history. Design history records changes in a linear fashion, from when design history was initialized to the present. Branching is not currently supported.

When enabled, design history becomes part of the DGN file. By default, revisions cannot be removed from the design history of a file and there is no way to modify historical information.

Once a revision has been committed, there are a number of viewing options. You can:

• Track all committed changes
• View changes on an element level
• Select changes via a list filter