AECbytes Product Review (June 12, 2013)

ArchiCAD 17

This review looks at the latest release of ArchiCAD, version 17, from Graphisoft, which has recently been released and started shipping this week. Looking back at the recent releases of ArchiCAD, every version has revolved around a theme: for ArchiCAD 13, it was collaboration with its BIM Model Server and revamped Teamwork interface; for ArchiCAD 14, the focus was on interoperability and open design collaboration with its Open BIM initiative; ArchiCAD 15 focused on expanding design freedom through the Shell tool; and ArchiCAD 16 expanded this further with the Morph tool, as well as improved access to BIM content through a new BIM Components portal.

For the new version, ArchiCAD 17, Graphisoft has chosen to focus on the problem of details, or in other words, enabling the construction documents to be derived automatically from the “live” building model without any re-work or touch-ups. Mies van der Rohe, who is considered the pioneer of modern architecture, famously exhorted that “God is in the details.” Graphisoft has cleverly turned this into the tagline, “BIM is in the details,” for ArchiCAD 17. Let’s take a closer look at how this has been actually tackled in ArchiCAD 17, along with other features in the new release including background processing, real-time 3D cutaways, and intelligent stories.

A More Detailed BIM

ArchiCAD 17 has two new features for enabling construction details to be added to a BIM model: they are called “Priority Based Connections” and “Intelligent Building Materials.” They work in conjunction with each other and are intended to simulate the way a building is constructed in real life, so that when the BIM model of the building is created in ArchiCAD, it automatically provides the structurally correct sections and details that would be needed for generating the necessary documentation and images.

The Priority Based Connections feature automatically cleans up the junctions of intersecting construction elements such as walls, beams, columns, slabs, roofs, shells, and morphs, which are the elements that are mainly involved in creating construction details. This is shown in Figure 1, where the top image shows a section display of a simple model in the “legacy” ArchiCAD mode, while the lower image shows the same section in ArchiCAD 17 with the connections between the junctions automatically cleaned up, based on how a building is actually constructed.

Figure 1. Effect of the Priority Based Connections feature in ArchiCAD 17. The top image shows a section without this feature activated, while the lower image shows the junctions automatically cleaned up.

The Priority Based Connections feature is enabled in ArchiCAD 17 by deselecting the option “Use legacy intersection methods for model elements” in the Project Preferences dialog for Construction Elements, as shown in Figure 2. By default, this option is turned off in ArchiCAD 17, so all new projects automatically have junctions cleaned up. But if a model is being imported from an earlier version of ArchiCAD, the “legacy intersection methods” option is checked. However, if it is deselected, ArchiCAD 17 goes to work on cleaning up all the junctions automatically, even those that are not visible in the current view. This happens without a noticeable slowdown of the application, thanks to its new “background processing” capability that will be described in more detail in the next section.

Figure 2. The Project Preferences for Construction Elements in ArchiCAD 17, showing the option that can be used to specify whether legacy intersection methods should be used or not.

The automatic cleanup of junctions shown in the lower image of Figure 1 is, in turn, done on the basis of the “intersection priority value” of the building materials that have been assigned to the elements. This intersection priority is a new property of materials which makes them more “intelligent” than before, hence the term Intelligent Building Materials to refer to the new feature. Many construction elements are composite structures, and the  automatic cleanup of junctions happens on a layer-by-layer basis. Materials with higher intersection priorities have precedence over materials with lower intersection priorities. This new “intersection priority” property of materials can be specified in the Building Materials dialog, as shown in Figure 3. The top image shows all the materials in the selected wall elements and their various properties, including the new Intersection Priority. You can see that the intersection priority of the concrete masonry material in the wall has a value of 700. Compare this to the intersection priority of the structural concrete of the slab, shown in the lower image of Figure 3, which is 750; you can now see why the junctions are cleaned up so that the concrete in the slab has precedence over the concrete in the wall.

Figure 3. The intersection priority of the building materials in the wall (top image), compared with those in the slab (lower image).

This new feature in ArchiCAD 17 can greatly speed up the creation of construction documents by automatically creating architecturally correct details from the BIM model. It allows the model to continue to stay “live” rather than breaking the link between the model and the construction documents, a practice that is still prevalent today among many architectural firms but should preferably be avoided as it does not allow them to reap all the benefits of the BIM workflow. The automatic cleanup of junctions also allow more accurate quantity-take-offs to be performed from the model, and provides better support for estimation and fabrication as well.

Needless to say, the new element libraries in ArchiCAD 17 come with the intersection priority value of the corresponding building materials already defined based on correct construction techniques, so that the automatic cleanup of junctions is accurate. For a different construction technique, the intersection priorities of materials can be adjusted to ensure correct junction clean-ups. According to Graphisoft, with the new Priority Based Connections feature, over 90% of the building details required for a project can come automatically from the building model, without any additional modeling work on individual junctions.

Other Key Enhancements

A key new feature in ArchiCAD 17 is the ability to define real-time 3D cutaway sections of the model graphically in 2D and 3D views, using one or more cutting planes in any location and direction. Once a plane has been defined, it can be moved around freely to display the desired cutaway. The use of advanced OpenGL technology for generating these cutaways enables the process to be relatively fast, even for a large model. The cutting planes can be horizontal, vertical, or even slanted. Multiple cutting planes can be defined and be active at the same time, allowing very specific views to be generated. Figure 4 shows a 3D cutaway of the model created by using three cutting planes, one horizontal, one vertical, and one slanted. The cutting planes used for generating a particular view are saved with the view, and can be displayed, if required. The option to display them has been selected in the cutaway view shown in Figure 4, and the cutting planes are shown by light gray planes.  These cutaway views can be very useful as a visual aid, displaying only the relevant parts of a model and allowing it to be checked for consistency, especially the interior parts that are usually difficult to visualize and inspect.

Figure 4. Three cutting planes applied simultaneously to a large model to generate a 3D cutaway view. The new cutting planes menu is also shown.

Recall from past reviews of ArchiCAD that one of its main limitations has been the lack of associativity, which means that changes made to any of the model elements do not automatically propagate down to the associated elements to maintain the connection between them. For example, when a wall is moved, the neighboring walls do not automatically stretch or shorten to maintain the connection—for this, you have to select the wall and its neighboring walls with a marquee and apply the Stretch command. As I pointed out in my review of ArchiCAD 15, this is such a basic feature in most BIM tools (including lesser-known BIM applications like Nemetschek Allplan and Vectorworks Architect) that not having it in ArchiCAD makes it stick out like a sore thumb.

In ArchiCAD 17, this limitation has been somewhat addressed at least for vertical connections through a feature known as “Intelligent Stories.” What it does is allow the heights of elements such as walls, columns and zones to be linked to a particular story (level) in the project, so that if the story position changes, the heights of the linked elements is automatically adjusted to maintain their connection with the story. This is illustrated in Figure 5, where the Settings dialog of the selected wall shows its Home Story as the 1st Floor and its top is linked to the 2nd Floor. Subsequently, when the story height is changed, the height of the wall and the position of openings in it are automatically adjusted to maintain the link. In contrast, for the interior wall, its Settings dialog shows that its top is not linked to any story, so it remains unchanged when the story height is modified. Elements like this will have to be adjusted manually to connect them to the new elevation of the slab.

Figure 5. The new property in the Settings dialog of a wall element to automatically link its top to a specific story allows it to be automatically adjusted to maintain its connection with that story when the height is changed.

ArchiCAD was already the pioneer in multi-processing and 64-bit support (see my review of ArchiCAD 13), which made it significantly faster, especially given the smaller file sizes of its models (compared to an application like Revit, which, like ArchiCAD, uses a centralized rather than a distributed approach  to storing project data). In ArchiCAD 17, its performance has been further enhanced by a technological innovation called “background processing,” giving it the distinction of having the industry’s first background processing for BIM. Unlike multi-processing, which allows the multiple processors in a computer to do multiple tasks in parallel for more computing-intensive processes, background processing in ArchiCAD allows a number of tasks to run in parallel, enabling the user to continue working on the model in the foreground, while the computer finishes other tasks in the background. A good example of a performance-intensive task that is speeded up significantly by background processing is the automatic junctions feature described in the last section, which happens not only for junctions in the current view but for all the junctions in a building, of which there could be thousands in a complex building model. You can see the background processing in ArchiCAD 17 in action by turning on the CPU Usage on a Mac, as in Figure 6, which shows the activity on all the cores of the computer working on a task. Although background processing has been implemented for tasks such as automatic junctions for now, it will be extended to work with other computer-intensive tasks in future versions. In addition to background processing, other performance improvements in ArchiCAD 17 come from the implementation of other new technologies including advanced OpenGL, optimized scaling of multiple-core CPUs, improved CPU performance, and code optimization within ArchiCAD itself.

Figure 6. Turning on the CPU Usage monitor on a Mac, which shows the multiple cores on the computer working together on a task that uses background processing.

Additional Improvements

There are several additional enhancements in ArchiCAD intended to improve its power and sophistication as a BIM application. The Morph tool that was introduced in ArchiCAD 16 has new scheduling features to better support conceptual design and mass modeling. You can now create massing model schedules that list the volume and surface area of morph conceptual masses separately by story, as shown in Figure 7, enabling the areas of the planned project to be checked against the program requirements at the conceptual design stage.

Figure 7. Generating a mass model schedule showing the area of a mass on each story of the building. The model shown here has three different masses, which were created using the Morph tool.

ArchiCAD already had the ability to easily create slanted and profiled walls, with the ability to modify them by simply changing their parameters. ArchiCAD 17 extends the ability to model non-linear forms by enabling the Beam tool to easily create beams that are curved on a horizontal plane, which can serve as support structures along curved walls. Other 3D modeling enhancements include the ability to create any construction elements in 3D with automatic surface recognition; a new graphical interface for the Roof tool that makes it easier to set its parameters; improved integration with SketchUp and Google Earth; and the ability to export BIMx models, enabling proposed projects to be explored, communicated, and shared with clients and other project team members in the form of interactive BIM project environments. (For more information on BIMx, please see the article “iPad Apps for AEC: Design and Visualization.”)

Other improvements in ArchiCAD 17 include faster loading of libraries because of a new caching process; access to more high-quality BIM objects through its BIM Components portal; the availability of a new option for editing a zone that allows its aspect ratio to be changed while maintaining its area; an improved energy evaluation engine (VIPcore from StruSoft) that supports multiple thermal blocks, allowing designs to be evaluated using standard compliant technology; and reiteration of its Open BIM commitment through extended IFC Model View Definitions to support many national and international standards, including IFC 2x3 (required by buildingSMART and other organizations), IFC 2x3 Coordination View (1.0 and 2.0),  Coordination View (Surface Geometry), Basic FM Handover View (required for COBie documentation), and Concept Design BIM 2010 (required by GSA in US, Statsbygg in Norway, and Senate Properties in Finland). The Publisher module in ArchiCAD 17 also allows IFC models with specific content to be easily exported to other disciplines—for example, the load-bearing structure to the structural engineer (see Figure 8), or the entire model to the MEP engineer.

Figure 8. Exporting a floor plan in the Publisher module of ArchiCAD 17 in the IFC format to a structural engineer using Tekla Structures. The content is automatically filtered so that it can be readily imported into Tekla Structures.

Analysis and Conclusions

From improved interoperability, to more design freedom, to better ability to model details—this has been a good trajectory for ArchiCAD to follow in its annual releases. At first glance, the automatic junctions capability does not seem as dramatic as the Shell tool or the Morph tool, but once you work with it, you have to appreciate the elegance and sophistication of the solution. By making junction clean-up dependent upon the intersection priority of the building materials that comprise the intersecting construction elements is smart as well as flexible—you simply can change the intersection priority values of materials to get the desired result if the construction style is different from the default.

It is important to keep in mind that the ability of automatically cleaning up junctions in ArchiCAD 17 is not the same as the construction modeling capability in Revit, which was introduced in Revit 2012 and continues to be expanded in every subsequent release. That allows contractors, or even architects, to add construction methods to building components, such as breaking up a wall into its individual layers or breaking up a single slab into separate parts based on the sequence in which it will be poured on site. Thus, ArchiCAD’s new capability is not going to necessarily help create models for construction sequencing. However, it can definitely help architects, and the construction documentation departments of design-build contractors, create more accurate models, which in turn can enable more accurate quantity take-offs, and allow 2D detail drawings to be derived from live sections of the model without too much re-work.

Another enhancement in ArchiCAD 17 that does not seem very dramatic at first glance is the 3D cutaways feature, as many other design and visualization applications already offer a similar capability to generate 3D sectional views. But after exploring this feature in ArchiCAD 17 for some time, I was struck by how easy it was to create multiple cutting planes, including custom ones, and position them to get desired views of the interior of a model. Adding this to performance improvements such as background processing, the continued commitment to interoperability, and the host of additional enhancements described in this review makes ArchiCAD 17 a solid release, both for its existing users as well as potential new users.

About the only improvement in ArchiCAD 17 that I was not so impressed with was the ability to link the tops of vertical elements with a specific story so that they are automatically adjusted to maintain the link when the story height is changed. This seems too little and too late, given that associativity is a common feature in BIM application—in fact, Revit had it from the start—and most users expect elements to automatically adjust to changes in neighboring elements, both horizontally and vertically. Graphisoft has maintained that this kind of associativity is equivalent to constraints that can hamper design freedom, but it could at least provide users with the choice to use associativity, as Bentley does with its BIM solution. It would have been nice if ArchiCAD had gone all the way in implementing associativity rather than restricting it to vertical elements only. Moving a wall in plan and not seeing the adjoining walls adjust to maintain the connection makes the application seem somewhat antiquated, belying the power and sophistication of the rest of the application. I hope Graphisoft makes it a priority to add horizontal associativity in addition to vertical associativity to ArchiCAD soon.

In conclusion, ArchiCAD 17 has many critical enhancements that continue to improve its BIM capabilities, many of which are superior to its competitors. I think it should turn its attention to making BIM more intelligent, as I described in my review of ArchiCAD 16. Its “automatic junctions” feature is a great start towards this—it is a smart and elegant way to eliminate one of the mundane and laborious tasks in creating a building modeling a building. Hopefully, we will see more of such intelligent, time-saving features in the application in the future.



About the Author

Lachmi Khemlani is founder and editor of AECbytes. She has a Ph.D. in Architecture from UC Berkeley, specializing in intelligent building modeling, and consults and writes on AEC technology. She can be reached at


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