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 default bolt hole size that you define in drawing properties. This attribute is for template purposes only.

The default bolt hole size (Ignore size) in the bolt mark properties defines the default size of bolt holes. This setting defines the size of bolt holes that do not have bolt marks in drawings.