Ceilings have a framing configuration assigned to them which you see when you display framing. You can specify a custom framing configuration if you want. The configuration consists of a joist member selection, joist spacing and joist direction. Framing can be displayed using the Display Framing tool, and is included in the project estimate.
To specify framing members for ceilings:
In non-framed view, select the ceiling you want to change. You can also specify framing members for ceilings in the catalog.
Right-click and select Properties, or select Edit > Modify Elements > Properties.
On the Basic property page, click the Specify Framing button.
To select a joist member, select Joist in the list, then click Select. Then, select the desired member from the Catalog Access dialog.
In the Joist Spacing edit box, specify the desired spacing between joists.
In the Joist Direction edit box, specify the direction in which you want the joists to run in degrees of an angle.
Click OK.