Create Roof Level Lines

Note: Roof Level Lines can be placed on both single-plane and multi-plane roofs. However, with multi-plane roofs, make sure you are not using legacy intersection mode. (Go to Options > Project Preferences > Legacy, and make sure that the “Use Legacy Intersection methods” checkbox is not active.)
The Design > Roof Extras > Create Roof Level Lines command, available in the Floor Plan, will place a line on a selected roof at the height value you specify in the Roof Level Lines dialog box.
On Top/On Bottom: Choose whether you want to measure the height value to the top or to the bottom surface of the roof.
Specify Roof Level Lines height level: Use either input field - the current story level or Project Zero - to define the height of the desired roof level lines.
Omit Lines Outside Roofs: Check this box to omit level lines that fall outside the floor plan polygon of the roof they belong.
Group with Roof: Check this box to group level lines with the roofs they belong to.
Note: This option is grayed if the Suspend Groups toggle is active.