How do I create a vaulted ceiling and scissor trusses?
In Chief Architect, roof trusses are generated in the space between the roof planes above and ceiling planes below. When a vaulted ceiling has a different pitch than the roof planes above, scissor trusses are produced.
To build the roof
Launch Chief Architect and Open the Chief Architect plan in which you would like to create scissors trusses.
In this example, a simple 20' x 30' rectangular plan is used.
Using the Select Object tool, select the walls to make gable ends, then click the Open Object edit button.
In this example, the left and right walls were selected.
On the Roof panel of the Wall Specification dialog, put a check next to Full Gable Wall and then click OK.
Select Build> Roof> Build Roof and in the Build Roof dialog on the Roof panel:
Put a check in Build Roof Planes.
Set the desired pitch in the Pitch (in 12) field.
For this example 10 in 12 pitch is used.
Put a check in Trusses (No Birdsmouth).
Click OK to build the roof.
To build the ceiling
Using the Select Objects tool, click in the room that will have a vaulted ceiling to select it, then click the Open Object edit button.
On the Structure panel of the Room Specification dialog, uncheck the box beside Flat Ceiling over this room, then click OK.
To make it easier to draw ceiling planes, select Tools> Layer Settings> Display Options and in the Layer Display Options dialog for the active layer set:
Scroll down to the Roof Planes layer and remove the check in the Disp column.
Click OK to close the dialog and turn off the display of the roof planes in the plan.
Select Build> Roof> Ceiling Plane from the menu.
Click and drag a baseline along a wall defining the room that will have a vaulted ceiling.
For best results, the baseline should be within the outside edge of the framing layer of that wall.
When the baseline is complete, click once in the room to set the ceiling planes ridge.
Click on the ceiling plane to select it, then use the edit handles that display to stretch it across the room to the inside surfaces of the gable walls.
In this example, two ceiling planes will form a ridge in the center of the room, so make sure the ridge edge of this plane does not extend past the middle of the room.
With the ceiling plane still selected, click the Open Object edit button and on the Ceiling panel of the Ceiling Specification dialog:
Make sure that the Inside bottom height is locked.
Specify the desired Pitch for your vaulted ceiling.
For this example 6 in 12 is used.
Click OK close the dialog and apply the change.
Repeat steps 4 through 6 to create a second ceiling plane opposite the first one.
Click on the ridge edge of one of the ceiling planes,
Click the Join Roof Planes edit button then click the ridge edge of the other ceiling plane.
The two ceiling planes will calculate pitch and distance and will join where the two planes would intersect.
If you wish, you can turn the display of roof planes back on in the Layer Display Options dialog.
To create scissor trusses
With both the ceiling and roof planes in place, you can now create roof trusses.
Select Build> Framing> Roof Truss from the menu.
Click and drag to draw a roof truss perpendicular to the ridge line of the roof and ceiling planes.
Click on the truss to select it and move it so that the exterior edge of the truss is aligned with the exterior edge of the framing layer of the wall.
Note: By default, trusses will snap to align over an outer wall, or to the corner of a roof plane. This can be prevented to allow for manual control of the truss by checking "No Special Snapping" on the General panel of the truss's specification dialog.
With the truss still selected, click the Multiple Copy edit button, then click the Multiple Copy Interval button to open the Multiple Copy dialog.
Verify that Offset Between Copies When Dragging is selected and that the Primary Offset specified for All Trusses equals the desired O.C. truss spacing, then click OK.
In this example, a primary offset of 24" is used.
Click and drag the truss's Move edit handle to create copies at regular 24" intervals.
The trusses over the walls on the ends will be a full size truss. If you wish to have end trusses instead, group select the end trusses and then open the "Truss Specification" dialog. On the General panel, put a check in "End Truss" and "Force Truss Rebuild," then click OK.
Select 3D> Create Perspective View> Perspective Framing Overview to see the results.