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.

Shows the top level of an assembly. Top level takes the unit and accuracy from the MarkDimensionFormat.dim file. You can modify the settings in MarkDimensionFormat.dim in the Dimension Properties dialog box in a drawing.

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