Use this command (Design > Roof Extras > Create Roof Level Lines) to place a Line on a selected Roof at the height value you specify.
After you place the Roof Level Line, you can place a Level Dimension there to indicate the elevation.
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.)
1.On the Floor Plan, select a Roof.
2.Use Design > Roof Extras > Create Roof Level Lines,
3.Set preferences in the appearing dialog box, then click OK.
–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.
If the checkbox is disabled, all resulting lines will be drawn. In this case, lines that fall outside the roof polygon will be drawn to be of equal length to the pivot line of the roof they belong to.
–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.
See also Level Dimensions.