This is a template attribute. Template attributes can be used in filtering, or to retrieve data from the model to use in drawings and reports. For example, when you create a report, Tekla Structures replaces the attributes added in the report template with the corresponding object property values.

This attribute shows the top level of an assembly. Top level takes the unit and accuracy from the MarkDimensionFormat.dim dimension property file. You can modify the settings saved in MarkDimensionFormat.dim in the dimension property pane in a drawing.

You can use this attribute as a user-defined attribute also in part marks and associative notes.