It is advisable to define data tables before creating any sightlines that use them. Data tables are simply lists of values.
Click the Tables button on the Visibility page. The Tables dialog is displayed. Select the required table from the drop down list.
The table values are pre-defined and will display in the panel.
You may edit the values in the table but not the units.
To add a row of data, click Add Row. A row is inserted before the highlighted row. To add a row at the end of the table, deselect all rows and click Add Row.
To delete a row, highlight it and click Delete Row.
Click Copy to make a duplicate of an existing table for modification.
Click New to create a new table. The New Table dialog is displayed.