I need to create a flared skylight shaft. How can I do this?
The settings in the Roof Hole/Skylight Specification dialog allow you to control how the roof hole is cut through the roof plane, but not how it builds down to the ceiling below. If you need the skylight shaft to be flared, though, you can accomplish this by displaying and editing the ceiling hole polyline associated with the skylight shaft.
To create a flared skylight shaft
Open the plan in which you wish to create a flared skylight shaft.
Select Build> Roof> Skylight from the menu, then either:
Click and drag within a single roof plane to draw a rectangular skylight; or,
Click once to place a 2' x 2' (600 mm x 600 mm) square skylight.
Click the Select Objects button, then click on the skylight to select it and click the Open Object edit button. On the General panel of the Roof Hole/Skylight Specification dialog:
Specify the Angle for Inside Hole Rim, which is the angle that the skylight is cut into the roof plane. Choose Square Sides for cuts that are perpendicular the roof pitch, Plumb Sides that are vertical, or Plumb/Square for a plumb cut on the lower end of the skylight and a square cut on the higher end.
Check the box beside Manually Edit Ceiling Hole Polyline.
Click OK to close the dialog and apply your changes.
Notice that there are now two polylines at the location of the skylight - one for the skylight itself, and a second, larger one for the ceiling hole polyline.
Select 3D> Create Orthographic View> Backclipped Cross Section from the menu, then click and drag a camera arrow that both begins and ends inside the skylight polyline.
Select CAD> Lines> Draw Line from the menu, then click and drag a line representing the desired angle of the skylight well.
If a specific angle is needed, you can type it in the Line Specification dialog.
In this example, the side of the well nearest to the roof ridge will have a downward angle of 75°.
Select Window> Tile Vertically to tile your floor plan view and cross section view windows next to one another.
Click in the floor plan view window to activate it, then click the Select Objects button and click on the larger ceiling hole polyline to select it.
Use polyline's edit handles to extend it in the appropriate direction, then release the edit handle to see the results in the cross section view.
Continue adjusting the ceiling hole until the edge of the skylight shaft meets up with the CAD line.
Bear in mind that a roof hole, skylight, or a ceiling hole associated with a skylight must exist entirely within a single roof plane. If the ceiling hole extends past the ridge, or other edge of the roof plane, it and the skylight shaft will disappear.