# DGN Additional Properties \[SIG]

For the definition of DGN Additional Properties to be meaningful, the file must be exported in the MicroStation (\*.dgn) format.

The Additional Properties section in a DGN file allows you to attach custom, user-defined information to DGN 3D elements when exported. This is especially useful in digital delivery projects, where adding metadata to objects is important.

**Objects:** This parameter specifies the 3D object or objects to which the Additional Property definition will be applied.\
To select the object or objects, click the three-dot button next to the Object parameter. In the interface that appears, click the Pick button, then choose the desired object or objects.

![image-20250929-221746.png](https://openbrim.atlassian.net/wiki/download/attachments/3290497056/image-20250929-221746.png?api=v2)

**Property Name:** This is the name of the attribute you want to define or attach.\
Examples include:\
\- Bridge ID\
\- Span ID\
\- Span Length\
\- Girder Length\
In other words, it defines what kind of information you are adding.

**DGN Value Type \[Text/Number]:** The data type of the property value, indicating whether the entry is stored as text or number. **Text Value:** The property's value when defined as text. **Number Value:** The property's value when defined as a numeric entry, often linked to calculations or measurements. You can either assign a parametric value or reference another cell in the project by using the Copy Parameter action in the spreadsheet. The numeric value is always entered/stored in the internal unit system: inches for length and kips for force when using the imperial unit system.

![image-20250929-221307.png](https://openbrim.atlassian.net/wiki/download/attachments/3290497056/image-20250929-221307.png?api=v2)

![image-20250929-221319.png](https://openbrim.atlassian.net/wiki/download/attachments/3290497056/image-20250929-221319.png?api=v2)

![image-20250929-221354.png](https://openbrim.atlassian.net/wiki/download/attachments/3290497056/image-20250929-221354.png?api=v2)

**Unit of Measure \[L.F./S.F./C.F./C.Y./LB./TON/EACH/L.S./HR/EST./CALC/S.Y./ACRE/MI./GAL./CM/DAY/MGAL/MBM/UNIT/HUND/CRHR/PLS/DEGREE/STATION(ft)/STATION(US ft)]:** The unit associated with the numeric value, ensuring consistency in interpretation.

**Final Value (Read-Only):** Displays the numeric value expressed in the specified unit.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.openbrim.org/templates/steel-i-girder-bridge-workflow/export-sig/dgn-additional-properties-sig.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.