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AECbytes Tips and Tricks Issue #42 (May 22, 2009)

The Curtain Wall Tool in ArchiCAD 12

Jeff Olken
ARCHVISTA Building Technologies

In this Tips and Tricks article, we will learn how to take advantage of the flexibility of ArchiCAD’s Curtain Wall tool, which is designed to easily fabricate modular glazing systems. The image below shows an example, in which a glazed atrium has been created using four separate systems that are interconnected. The two sloping curtain walls also connect to the adjacent solid walls. The vertical system consists of three segments, and along with the horizontal system, they were used to cut a hole within the sloping wall for the opening. The horizontal “transoms” were adjusted so that the patterns of the vertical and sloping systems coincide appropriately.

Introduced in ArchiCAD 12, the new Curtain Wall Tool features advanced technology that provides design control of an overall building system while allowing for the customization of individual elements. We can use this tool to represent a wide variety of repetitive construction methods, including detailed suspended ceilings, framing, pre-cast panels, sunrooms, and more. Because the tool allows for customization of individual components, virtually any design can be represented and refined.

Defining a Curtain Wall

Creating a curtain wall begins with defining a pattern. To define the pattern, double-click the Curtain Wall Tool in the toolbox. Once there, select the Scheme option from the list on the left.

The pattern consists of a rectangular grid of Main and Distinct panels. The grid itself can be as complex or as simple as desired, and each cell of the grid can be assigned to either panel class. As seen in the image below, white cells denote “Main” panels and grey cells refer to “Distinct” panels. This pattern repeats across the span of the curtain wall system.

Once the pattern has been specified, the other components of the curtain wall can be addressed at any level of detail.

Creating a Deck

Like all tools in ArchiCAD, the Curtain Wall tool is flexible enough to solve a variety of secondary challenges. In this case, we will look at modeling an exterior wooden deck articulating the individual framing and decking members. As we will see, one curtain wall will represent the framing, and a second system will model the decking.

First, let’s develop a pattern for the framing: Set the Primary Gridline to 2’ which will become the joist spacing distance. Set the Secondary Gridlines to 100’ to ensure continuous joists. Alternately, we could set the value to the maximum joist length, and ArchiCAD would automatically generate a perpendicular framing member.

Next, we need to assign the appropriate sizes for the frames. We can use the Uniform Frame Classes button to eliminate repetitive entry for the boundary frames and the mullion frames.

We don’t want the panels, but the Curtain Wall Tool doesn’t have an option for not placing the panels initially, so we’ll need to edit them out later.

Finally, we need to control the positioning of the system. Select Curtain Wall System from the component list on the left. In the Positioning section of the dialog, set the Nominal Thickness to match the joist size. Then set the Boundary and Mullion offsets to the negative of the frame size, in order to force the framing to extrude downward from the reference plane of the system.

Now we’re ready to outline the deck framing. We need to choose the Boundary geometry method to create a horizontal system.

Once you have completed the outline of the deck, click inside the polygon with the Sun cursor. We’ll use the Boundary Frames to represent the rim joists, and the Mullion Frames will become the joist members. In this example, we won’t use the Transom Frames, but they could be used to represent blocking.

To remove the panels, select the element and click the Edit note in the center. Once you are in Edit mode, you can click on the Panel Tool in the toolbox, then simply choose Select All from the Edit menu, and delete all of the panels in one quick operation. Once the panels have been removed, accept the changes and exit edit mode by clicking OK on the Curtain Wall editing control panel.

Because this is a system, we can adjust the spacing of the joists, the framing member sizes, and material representation of the overall system easily. To change the lumber size from 2x10 to 2x12, for example, select the framing, double-click the Curtain Wall tool, and update the frame dimensions. Click OK, and the lumber sizing will update. To change the distance between joists, select the frame and open the Curtain Wall Settings as before, but this time change the Scheme width.

Next, we need to repeat the process, but this time we’re placing the decking material. While the joist system used the Frame components and eliminated the Panels, the decking requires the opposite approach. We’ll use a similar Scheme, but we’ll set it to be horizontal instead of vertical. This step will eliminate the need to edit the system after we construct the outline. Set the Primary Gridline to 100’ and the Secondary Gridline to 6”. Also, as before, set the Pattern position to Start with Segment.

Next, set all of the dimensional parameters of the frames to 0”, and the Frame type to Invisible so that we have a gap between the decking members. A quick click of the Uniform Frame Classes button, and we’re ready to specify our panels.

In this case, we only have a Main Panel type, and we only need to set the panel thickness and materials to match the decking material.

Again, before drawing the outline of the deck, set the Curtain Wall System Positioning to match the thickness of the decking. Note the offset is to the center of the decking, and is therefore half of the value of the thickness.

Trace the outlines of the Frame System, and our decking is now in place. If we have done everything correctly, the decking should sit perfectly on top of the framing. We can also easily position the framing and decking height in a section window if needed.


The Curtain Wall Tool is highly flexible, and this article only highlights one of the many uses of this powerful design tool. Once you’ve followed the steps of making a deck, try your hand at using these techniques to create a custom railing for your deck using a vertical Curtain Wall System.

If you’re interested in furthering your knowledge on this topic, we offer a series of 6 recorded classes focused on the Curtain Wall Tool as part of your LearnVirtual membership, plus over 110 recorded classes and weekly LIVE eClasses on a range of topics including modeling techniques, drafting techniques, process management, revision management, rendering and animation. To learn more about LearnVirtual, go to

About the Author

Jeff Olken has focused on the implementation of Building Information Technologies throughout his career and has spoken at major industry events across the U.S., including the AIA convention, AEC Systems, and ArchiCAD University. He was formerly with Graphisoft U.S., Director of Technology with DNM Architects, and General Manager for TECbuild. He earned a B.A. in Architecture from UC Berkeley in 1993, and returned to teach ArchiCAD in 1994-1995. He earned his MBA in 2001. He can be reached at

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