NUMBER_VISIBLE
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.
When added in the reinforcing bar group mark, shows the number of visible reinforcing bars in the view that have the same position number. This is a context-specific template attribute.