Civil Cells and Feature Definitions
Civil cell names used in a dgn file must be unique, and follows the same incremental naming used for civil feature naming. Civil cells provide a container for all geometry features and civil objects (linear templates, area templates and corridors) held inside.
Civil cells, acting as a unique container id, preserve feature definitions and feature names defined inside them, and carry the same names forward to each new instance. The resulting new features remain unchanged in each new instance of the civil cell because the civil cell names maintain the unique identification of all objects contained inside.
For example, horizontal geometry named "Approach" can reside in the current design model as well as any number of civil cells (for example in civil cells named Type 1, Type 2, and Type 3). Although in this example there are 4 instances of the same feature, they are all uniquely identifiable due to the additional instances residing in the civil cell whose name makes all instances unique. When the cells are dropped the features and objects contained in them are renamed according to the standard renaming increments and they adopt the next available name.