A dropped ceiling is a secondary ceiling, hung below the main, structural, ceiling. They may also be referred to as a drop ceiling, false ceiling, or suspended ceiling.
To create a dropped ceiling
Open the plan file in which you need to create a dropped ceiling.
Click the Select Objects button, then click in an empty space inside of the room that you want to assign a dropped ceiling to select it.
If you select an object inside of the room, click the Select Next Object edit button or press the Tab key on your keyboard until the room becomes highlighted.
With the room selected, click the Open Object edit button.
On the Structurepanel of the Room Specification dialog, click the Ceiling Finish Edit button.
In the Ceiling Finish Definition dialog:
Select Layer 1 of the ceiling finish definition, then click the Insert button to add a new layer above the selected layer.
Specify the desired Thickness of the new layer, which will form the dropped ceiling framing. In this example, 3 1/2" is used.
Click either the Library or Plan Material dialog and specify the new layer's material as a Framing material. In this example, "Framing Fir Stud 16" OC is used.
Specify the Structure Type, which is the type of framing you want to use to frame the dropped ceiling. In this example, "Lumber" is used.
Repeat these steps if you require additional layers, such as an air gap, above the framing.
When you are finished, click OK to close the Ceiling Finish Definition dialog and return to the Room Specification dialog.
Notice that the preview diagram represents the Finished Ceiling (F) height.
The results can also be seen in a Backclipped Cross Section view.
To manually frame a dropped ceiling
If part or all of the platform above the dropped ceiling is a ceiling platform, a dropped ceiling's framing can be created automatically when Ceiling Framing for the floor is generated using the Build Framing dialog.
If, however, the entire platform above the dropped ceiling is a floor platform, the framing must be drawn manually.
Select the room with the lowered ceiling and click the Open Object edit button. On the Structurepanel of the Room Specification dialog:
Make a note of the Absolute Ceiling height.
Click the Ceiling Finish button and make a note of the Thickness of the layer or layers located above the framing layer.
Click Cancel to close both dialog boxes.
Subtract the thickness of the ceiling finish layers above the framing layer from the Absolute Ceiling height. The resulting value is the top height of your lowered ceiling framing members.
In this example, this height is 89 1/4".
Select Build> Framing> General Framing from the menu, then click and drag to draw a framing member across the room with the lowered ceiling.
Click on the joist to select it, then click the Open Object edit button. On the General panel of the Framing Specification dialog:
Specify the desired Width and framing Type. In this example, 1 1/2" thick Lumber is used.
Specify the desired Depth, then click the radio button beside Depth to lock this value. In this example, 3 1/2" is used.
With the Depth locked, specify the desired Top Height. Use the value you determined in steps #1 and 2, above: 89 1/4" in this example.
Press the Tab key on your keyboard to update the dialog, then confirm that your changes are all correct.
On the Line Style panel of the Framing Specification dialog:
Click the Layer drop-down list and select "Framing, Ceiling Joist" from the list.
Click OK to close the dialog and apply your changes.
With the framing member still selected, click the Object Layer Properties edit button. In the Object Layer Properties dialog:
Click to place a check in the Display column for the "Framing, Ceiling Joists" layer and click OK.
If you deselect the framing member before turning this layer on, or in version X3, select Tools> Display Settings> Display Options from the menu and turn on the "Framing, Ceiling" layer in the Layer Display Options dialog.
Move the framing member into position along the inside surface of a wall's Main Layer using whatever method you prefer. For example:
Using its Move edit handle,
Using a dimension,
Using the Transform/Replicate Object edit tool.
Once the framing member is positioned against a wall, select it and click the Multiple Copy edit button, then click and drag to produce copies at regular intervals.
You can specify the intervals by first clicking the Multiple Copy Interval edit button.
You can add ledger boards for the lowered ceiling joists using the same steps:
Draw a General Framing object;
Edit its Depth, Height, and other attributes as needed;
Move it into position against a wall.
To trim the dropped ceiling joists so that they butt against the ledger instead of extending into it, use the Trim Objects edit tool:
Zoom in on the ledger so you can see it clearly.
Click on the ledger to select it;
Click the Trim Objects edit tool;
Click and drag to draw a temporary fence inside of the ledger and through the joists that you wish to trim.
When you release the mouse button, all joists touched by the temporary fence will trim to the edge of the ledger.
You can now see the lowered ceiling framing in a Backclipped Cross Section if you turn on the display of the "Framing, Ceiling" layer in that view.