Creating a Mantel Using Crown Molding

Reference Number: KB-00503
Last Modified: July 16, 2015

The information in this article applies to:

Chief Architect Premier or Chief Architect Interiors


I would like to create a fireplace mantel using built-up crown molding. How do I do this?


Starting in Chief Architect X4, multiple moldings can be assigned to objects like cabinets, rooms, and molding polylines - and both vertical and horizontal offsets can be specified to produce built-up moldings.  Using the methods described here, you can also create a cornice, or built-up crown molding, around a room.

To create a molding polyline

  1. Open the Chief Architect plan in which you would like to create a custom mantel using crown molding.

    • In this example, a fireplace insert is placed against the wall. 

    • Pilasters on either side are of the insert are created using specially edited base cabinets.

  2. Zoom  in on the area of your plan where you would like to draw the molding.

  3. Select Build> Trim> Molding Line  from the menu, then click and drag to draw one or more lines that follow the edges of the mantel that will face the room.

    • In this example, the molding polyline displays in red around a fireplace insert and pilasters so that it can be easily seen.

    • You may find it helpful to draw the edges longer than necessary to start with, and then use the edit handles to adjust the shape and size of the polyline once it is drawn.

    • Depending on your plan, you may also find it helpful to temporarily toggle off Object Snaps .

  4. Using the Select Objects  tool, click on the newly created molding polyline, and select the Open Object  edit button . 

  5. On the General panel of the Molding Polyline Specification dialog, specify the Height of the polyline which will represent the bottom edge of the mantel when finished.

    In this example, the Height is 72". 

  6. On the Moldings panel:


  • Click the Add New button and browse the Moldings library to select a molding profile for the bottom part of the mantel.

  • Specify the desired Height and Width.

  • Keep the Offset values at 0".

  • Make sure that the radio button beside To Bottom is selected.

  • Remove the checkmark next to Extrude Inside Polyline

  • On the Line Style panel, select a distinctive Color and increase the Line Weight to 5.

    In this example, molding CA-67 is assigned a Height and Width of 3" with red lines

  • Click OK to close the Molding Polyline Specification dialog and finish creating the first molding polyline that will form your mantel. 


  • Select 3D> Create Orthographic View> Backclipped Cross Section  from the menu, then click and drag a camera arrow towards the fireplace to see the results so far. 

  • To build up multiple molding polylines

    1. Close the cross section view to return to plan view.

    2. Select Edit> Preferences  from the menu to open the Preferences dialog.  On the Behaviors panel:

      • Click the radio button beside the Concentric Edit Type.

      • Specify a Jump distance, which is the increment that an object will jump as it is being resized.

      • In this example, a Jump distance of 1" is used; however, depending on the dimensions of the molding profiles you select, you may prefer a smaller distance such as 1/2" or 1/4".

      • Click OK to close the dialog and apply your change.

    3. Click on the molding profile created above to select it, then click the Copy/Paste  edit button.

    4. Zoom  in on a corner, then carefully drag the corner edit handle outward. 

      • As you drag, notice that when you reach the Jump distance from the original, an image of the polyline displays.

      • Continue dragging until you reach the outside edge line of the original polyline.  Release the mouse button and a copy of the molding polyline will be created at that location.

      • In this example, the copy is dragged two Jump increments because the original molding profile has a Width of 2".

      • Once a copy is created, you can use the corner edit handle to resize it, if needed. 

    5. With this new copy selected, click the Open Object  edit button to open the Molding Polyline Specification dialog.

      • On the General panel, specify a Height for this polyline equal to the Height of the first polyline plus that first polyline's Height.  In this example, the height is 72" + 2", or 74".

      • On the Molding pane, click the Specify button and browse the Moldings library to select a molding profile for the second tier of the mantels molding.

        Also on the Molding tab, specify the desired Height and Width of this second molding profile.  As before, the Offset should be 0", To Bottom and Inside should be unchecked.

      • On the Line Style panel, select a new, distinct Color for this polyline.

        In this example, molding CA-19 is assigned a Height and Width of 3" and blue lines.

      • Click OK to close the dialog and apply your changes.

    6. Select 3D> Create Orthographic View> Backclipped Cross Section  from the menu, then click and drag a camera arrow perpendicular to the front of the fireplace to see how the molding profiles are stacked.

      • If needed, make any needed changes to the Height of either polyline in its specification dialog or modify its position using a corner edit handle.

    7. Repeat steps 1 through 5 as many times as needed to produce the desired mantel.

      • In this example, a third crown molding, CA-65, is added above the second and is assigned a Height of 3 1/2", a Width of 2", and green lines.

    8. Remember to select Edit> Edit Behaviors> Default  when you are finished editing your molding polylines. 

      You can also select the
      Default Edit Type in the Preferences dialog. 

    9. Add a hearth and accessories to your fireplace, then select 3D> Create Perspective View> Full Camera  from the menu, then click and drag a camera arrow towards it.