Creating a Flared Skylight Shaft

Reference Number: KB-00948
Last Modified: July 16, 2021

The information in this article applies to:

Chief Architect Premier or Chief Architect Interiors


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

  1. Open  the plan in which you wish to create a flared skylight shaft.

  2. Select Build> Roof> Skylight  from the menu, then either:

    Square skylight placed in a roof

    • 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.

  3. Using the Select Objects  tool, click on the skylight to select it, then click the Open Object  edit button. On the General panel of the Roof Hole/Skylight Specification dialog that displays:

    Roof Hole/Skylight Specification dialog

    • Specify the desired Inside Hole Rim option, which is the angle that the skylight is cut into the roof plane. Choose Square Sides for cuts that are perpendicular to 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.

  4. Notice that there are now two polylines at the location of the skylight - one for the skylight itself, and a second one for the ceiling hole polyline.

    Skylight with a ceiling hole displayed in floor plan view

  5. 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.

    Creating a Backclipped Cross Section view of the skylight and ceiling hole

  6. In the section view, select CAD> Lines> Draw Line  from the menu, then click and drag a line representing the desired angle of the skylight well.

    Drawing a CAD line at a specific angle

    • If a specific angle is needed, you can type it in the Line Specification dialog.

    • In this example, the CAD line is set to have an angle of -105°.

  7. Select Window> Tile Vertically  to tile your floor plan view and cross section view windows next to one another.

    Tile both the floor plan and backclipped cross section windows

    • Click in the floor plan view window to activate it, then click the Select Objects button and click on the ceiling hole polyline to select it.

  8. Use the ceiling hole 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. 

    Adjust the ceiling hole in floor plan view

  9. Continue adjusting the ceiling hole until the edge of the skylight shaft meets up with the CAD line.

    Skylight hole adjusted to be at -105°

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.