AECbytes Product Review (July 14, 2011)
Last month, we took a detailed look at the capabilities of the new release of Revit Architecture 2012, in which the new features and enhancements are spread out across many different aspects of the application rather than focused on one or two main themes. In contrast, the new release of ArchiCAD, a competing BIM application, is focused on the theme of “design freedom” and includes new tools and features that greatly expand ArchiCAD’s ability to model freeform buildings while still retaining the BIM nature of the model.
I find it very interesting how Graphisoft usually takes on a specific theme for a new release of ArchiCAD and then tackles that in a very comprehensive manner, such as it did for ArchiCAD 13 with its BIM server and improved model-based collaboration capabilities—which other BIM applications are still attempting to catch up with. In the same way, ArchiCAD 15 tackles its earlier lack of built-in freeform modeling tools head-on, with a brand-new Shell tool that is capable of modeling a broad spectrum of forms, a revamped Roof tool that allows quick modeling of complex roofs, and several interface enhancements that make 3D modeling easier and more accurate.
Other key enhancements in ArchiCAD 15 include support for renovation and refurbishment projects with a new Renovation palette providing the relevant functionality, improvements to its IFC interface and open collaboration workflow with engineers, full 64-bit support for the Mac OS, and improvements to its parametric object libraries. Let’s take a detailed look at these new features. (A more comprehensive evaluation of ArchiCAD vis-à-vis other architectural BIM applications can be found in the BIM Evaluation Study Report.)
Graphisoft was inspired to take on the theme of design freedom for its new release of ArchiCAD by looking at the history of architecture, both ancient and modern, which is replete with examples of freeform building shapes (see Figure 1). The older examples that are shown in Figure 1 were designed using paper and pencil alone, which had the advantage of being able to represent almost anything. The newer examples shown are from the pre-BIM era, which means that they were accomplished using CAD, which had the advantage of being able to draw freeform shapes but did not provide any assistance with the design process as such, since it did not carry any intelligence about the elements it was representing. In contrast, BIM has the potential to be a full 3D design and documentation tool, but so far, it has been limited in its capability to enable architects to freely conceptualize and design buildings with non-traditional forms.
Figure 1. A snapshot showing examples of both historical and modern architecture with freeform building shapes. (Courtesy: Graphisoft)
BIM tools such as Revit have greatly improved their conceptual modeling tools in recent releases, but in most cases, the freeform capabilities can only be applied to the conceptual model, which is then used to generate the BIM model. Thus, any change to the form of the building has to be applied to the conceptual mass first and is then propagated to the BIM model, resulting in an interrupted, less-than-optimal workflow. Ideally, it should be possible to create freeform building shapes directly in the BIM model, so that any required change can be made directly to that model rather than to a separate conceptual model. It is precisely this that ArchiCAD 15 sets out to achieve, with a new Shell tool that allows freeform BIM elements to be created, a greatly expanded Roof tool, as well as interface enhancements that make 3D modeling, editing, and navigation easier and more accurate. Let’s start by looking at the Shell tool.
The Shell tool is the main new freeform BIM tool introduced in ArchiCAD 15. It has three different geometry options, Extruded, Revolved, and Ruled, which allow you to model a wide variety of forms, as shown in Figure 2. Each option has both a simple construction method for creating a basic shell of that type quickly, as well as a more detailed construction method, which allows you to draw a more complex profile for creating the shell, as shown. The shell profiles can be created in any view and can also be edited graphically in any view to modify the resulting form. The recent 3D interface enhancements, which will be discussed in more detail in a later section, make it much easier to create and edit shell profiles in the 3D window.
Figure 2. The three different types of shells that can be created with the Shell tool, shown from top to bottom: Extruded, Revolved, and Ruled.
In addition, there are a large number of parameters that can be used to fine-tune the shell as required. Basic parameters include the shell thickness and the positioning of the shell body with respect to the defining membrane generated from its profiles. Additionally, there are three angles—starting, ending, and distortion—that can be used to change the orientation of the defining profiles and thereby dramatically alter the shell membrane and the resulting shell form, as shown in Figure 3. You can specify the material of the shell, which can also be a composite structure. The shell is correctly shown in plan, elevation, and section views, including all of its layers if it is made of a composite material.
Figure 3. The effect of changing the starting, ending, and distortion angles on a simple extruded form created with the Shell tool. The original shell is shown in the top image, while the revised shell is shown in the lower image.
Once a shell has been created, you can easily create skylights or holes in it, as shown in Figure 4. Walls and 3D zones can be trimmed against the shell, and they maintain their associativity so that if the shell element is modified, the walls and 3D zones automatically adjust to the new shape. To ensure that the shell is a BIM object, it can be classified as a roof or slab element and thus remains true to the BIM nature of the model. This allows it to be exported to the IFC format for interoperability with other BIM applications. It can be scheduled just like any other element, with accurate calculation of geometric properties such as surface area, volume, etc. Its quantity takeoff is also accurate, even if it is a composite structure—all its individual materials are calculated accurately.
Figure 4. Adding skylights to the extruded shell object shown in Figure 2. The 3D zone shown below has been trimmed against the shell element.
Thus, as you can see, the new Shell tool supports the broadest spectrum of architectural shapes for building structures that are prevalent in both historic and modern architecture. These structures, when created in ArchiCAD 15, remain an organic part of the entire BIM workflow without the need for conversion at any stage of the process, following the basic premise of the application that conceptual design should begin directly in the BIM model and architects should not have to create a separate conceptual model. They should be able to start any design with BIM elements from the first click, and should be able to modify any element freely. Also, the freeform modeling capability supports the entire architectural workflow, ranging from concept design to design development to construction documentation, because there is no “concept” or “massing” model separate from the BIM model.
While the new Shell tool is primarily intended for building modeling, it is flexible enough to be used for product modeling as well. However, generic 3D modeling applications do have a broader set of tools and interface features to support product design, so it is unlikely that ArchiCAD 15 would be used by product designers instead of these applications. But it will certainly help those architects already using it to venture beyond building design and use the application for modeling furniture and other interior design elements, if required.
In ArchiCAD 15, the existing Roof tool has been completely overhauled to make it much easier to model complex roofs, which are still a significant architectural element in many building types. There is a new Multi-plane geometry method for roofs that can be used to create a complex roof—which includes multiple planes and several roof levels—as a single roof element. You can select the series of points that will form the base of the roof (which would typically be the outer corners of walls or the corners of a zone), or use the Magic Wand tool to select a closed set of walls or a 3D zone, which will “magically” create the roof, as shown in Figure 5. The Magic Wand can also be used to add additional portions to the complex roof, or cut holes in it for atriums and courtyards, as shown.
Figure 5. The Magic Wand was used to automatically create this complex roof over a 3D zone, including adding portions to it for the two corridors and subtracting a part of it for the central courtyard.
The roof is created with the default settings, which can be modified in the Roof Settings dialog, such as the angle, pitch, eave offset, materials, number of edges in a curved roof, and so on. You can also edit the roof geometry interactively, using the large number of pet palette options that are available when you click on an edge or a plane of the roof. The roof geometry can be changed as a whole or you can make changes to individual planes, for example, changing their pitch, making them a gable, changing their material, fill, or eaves overhang, and so on. Because the complex roof is created as a single element, it is fully associative, so that any change made to a point, edge, or plane propagates intelligently through the entire roof, maintaining its connections and configurations, as shown in Figure 6. Roofs can also be trimmed against each other, and any subsequent changes to them continue to maintain their connectivity.
Figure 6. Editing a complex roof maintains its associativity, along with its connections to neighboring roof objects it has been trimmed against. In this example, the pitch of one of the corridor portions of the roof has been increased from 30° to 60°.
It should be noted that while walls and 3D zones can be trimmed against roofs, and roofs, in turn, are associative with each other, this associativity does not exist between walls/zones and roofs. This means that a roof is not automatically reshaped when the walls or the zones used to derive it are modified. So if there is any change in the spatial configuration of the design, the roof will have to be manually modified—it can be generated from the floor plan but does not stay associated with it.
Just as with shells, you can also add openings and skylights to roofs. In ArchiCAD 15, the Skylight tool has been enhanced to better support adding skylights to complex roofs and shells. They can be placed on flat as well as curved surfaces and appear accurately in floor plan representations by being true 3D vertical projections (see Figure 7). They remain associated with their parent roof or shell, adjusting and re-orienting themselves automatically when the geometry of that roof or shell changes.
Figure 7. Adding skylights to the simple curved shell shown in Figure 3. The second floor plan can also be seen, showing that the 2D representation of the skylights is accurate.
The new freeform modeling capability in ArchiCAD 15 is nicely complemented by some interface enhancements that make 3D elements easier to create and navigate. To start with, there are no primary or secondary view types to create or edit the BIM model—you can work in any view, 2D or 3D, and even in 3D perspective views (all of the ArchiCAD images above were created in a 3D perspective view). In contrast, in Revit, for instance, all the model creation and editing tools are deactivated in perspective views. It feels more natural for architects to work in perspective views, and ArchiCAD is now one of the only BIM tools to provide this capability.
Also, a new “editing plane” is now visible in the 3D window, allowing modeling elements to be created on a visible plane rather than in mid-air. This plane is dynamic, automatically enlarging as more elements are added to the model so as to accommodate all of them. You can use it to model elements more accurately by enabling a grid display on the plane at desired grid intervals and turning on Grid Snap; you can also enable the Tracker feature for precise coordinate input. By default, the editing plane is automatically set to the base elevation of the currently selected tool, but its position can be changed by changing the user origin. In addition, the editing plane can be rotated if required. For elements such as shells, the editing plane changes dynamically depending upon the position of the cursor detected on different surfaces, allowing points to be selected on them to create different shell profiles, as shown in Figure 8. You can also move the editing plane during an editing operation and position it where required to perform the operation more accurately.
Figure 8. The 3D editing plane is automatically repositioned on the surface on which a profile for a ruled shell is being created. In addition, the origin was repositioned at the corner of the surface and grip snap was turned on to draw the profile more precisely.
Another interface element in ArchiCAD 15 that has been greatly enhanced is guidelines, which are now available in 3D and can provide visual feedback when creating and modifying elements. These are displayed by default in orange dashed lines that are further highlighted by yellow bold lines when the cursor is moved along the X, Y, and Z directions, making it easier to follow the coordinate directions when required. Guidelines related to other elements, such as the extended line of a wall segment or the tangent of a circle, are displayed in blue dashed lines accompanied by orange dotted handlers; when these handlers are clicked, the corresponding guidelines are activated, displayed as orange dashed lines; they remain in the 3D window until the modeling or editing operation has been completed. Thus, you can have multiple guidelines displayed in the window at any time, if required, as shown in Figure 9, making it easier to create or edit 3D elements accurately in reference to other elements. Guidelines can also be dragged to different positions, if required. Guidelines can be projected onto the active working plane, allowing elements to be created that “match” existing elements but are in different locations or orientations.
Figure 9. Displaying multiple guidelines in 3D to accurately model an element in reference to other elements.
Other 3D interface enhancements in ArchiCAD 15 include the ability to snap to the intersection of the editing plane and existing elements, which ensures precise input even in case of curved or slanted geometry; better visual feedback when elements are selected, making it clear which elements are in front of other elements; and display of special editing lines, such as wall reference line, roof pivot polygon, etc., in their own specific colors, so that they can be selected more easily. All of these enhancements make it much easier for users to work in 3D and create and edit models more accurately and with fewer steps.
Although design freedom is the main theme of ArchiCAD 15, another key functionality it has added is improved support for renovation and retrofit projects, which are universally acknowledged to be on the rise compared to new building projects. It has introduced a new Renovation palette, which can be used to set the model to different “renovation filters”; this is accompanied by the ability to set the status of objects as to whether they are to be retained, demolished, or are part of the new construction. The renovation filters work in both 2D and 3D views. Figure 10 shows a renovation project displayed using different renovation filters, starting with the existing layout and progressively showing demolition plan, the plan after demolition, the new construction juxtaposed with the elements that will be demolished, and finally, the new construction by itself. As you can see, the different renovation filters show, hide, or override elements depending on their status.
Figure 10. A model of a renovation project seen through different renovation filters as shown in the Renovation palette.
The renovation filters can be customized using the Renovation Filter Options dialog (see Figure 11), where you can specify the exact display settings for existing, to-be-demolished, and new elements, along with different override styles including line type, color, material, etc. There are additional options that can be used to customize the filters to support different office standards or local standards in different parts of the world. You can also create new renovation filters if required. Overall, I found the new Renovation interface very simple and easy to use, yet effective in modeling renovation projects with the ability to easily specify and communicate which elements are new, which need to be retained, and which are to be demolished. This specific renovation functionality in ArchiCAD 15 is in contrast to other BIM applications which use generic phasing functionality to support renovation projects instead of supporting it directly.
Figure 11. The ability to customize the different renovation filters using the Renovation Filter Options dialog.
ArchiCAD 15 includes some additional enhancements on different fronts. On the interoperability front, the IFC interface has been improved to ease the process of model-based IFC exchange with other disciplines. The IFC properties of elements are now integrated into ArchiCAD tools and can be accessed and edited directly from the different element Settings dialogs, as shown in Figure 12. This allows IFC properties of elements to be specified more accurately and managed more easily. It also allows IFC properties to be transferred among elements, views and projects, just like any other native ArchiCAD parameters.
Figure 12. IFC properties are now available as native ArchiCAD parameters that can be accessed and edited directly from the different element Settings dialogs.
Import and export of IFC files is now almost twice as fast, thanks to a newer and faster IFC engine in ArchiCAD 15. Improvements have also been made to the IFC “compare and merge” functionality that was introduced in the last release. The Detect IFC Model Exchange workflow now allows you to choose and edit the preferred translator as you go, and model change entries can be better managed in the mark-up tool palette. You can now distinguish the modified elements coming from different versions of files as they are displayed in different styles. When merging an IFC file, you can define the ArchiCAD story to which the imported IFC model data should be mapped.
Another interoperability improvement is simplified model export. If the purpose in model exchange is to display model geometry only— such as in a viewer or in an MEP program—a simplified BREP (boundary representation) geometry export option is now available, which results in accurate geometric display of element intersections and solid operations, without including all element properties and data.
Other improvements in ArchiCAD 15 include the addition of several new objects to the ArchiCAD library in key focus areas such as sustainable design, medical and healthcare design, more contemporary visualization and furniture elements, and additional doors and windows. Library migration from older versions of ArchiCAD to newer versions is now easier. ArchiCAD 15 now provides full 64-bit support for the Mac, allowing ArchiCAD users on the Mac OS to take advantage of the increased memory management offered by 64-bit technology. There is an improved Autosave function that provides 100% data safety by continuously saving all changes in the background as you work. And finally, the BIM Server’s internal processes have been optimized, allowing a single BIM Server to manage multiple projects more efficiently, and speeding it up so that the send and receive response time is slightly faster.
With version 15, ArchiCAD has comprehensively addressed what has been one of its main limitations so far: the inability to create freeform BIM elements within the application. In fact, this is a limitation that its main competitors still have, so just as with the BIM server and collaboration enhancements introduced in ArchiCAD 13, Graphisoft once again comes out on top with ArchiCAD 15. The new Shell tool, with its ability to create extruded, revolved, and ruled forms, along with the large number of parameters and interactive editing options, allows virtually any building form to be modeled. Graphisoft has a number of videos on its website demonstrating how different historical and contemporary buildings with non-rectilinear forms have been modeled using the Shell tool. I was impressed with how substantively it has been implemented, in contrast to the typical rudimentary options available for a new tool—you would never think that it hasn’t been part of ArchiCAD’s repertoire for a long time.
Of course, ArchiCAD is still missing dedicated conceptual design tools that let you create massing models quickly, let alone those with organic forms. This is one area that Revit has made great improvements in within the last two releases, and Bentley has also implemented various enhancements including a Push/Pull capability similar to SketchUp’s to make it easier and more intuitive for creating massing models with its design solutions. No doubt, there is no seamless connection between the massing model and the detailed building model in either of these applications—there is still some kind of mapping or conversion involved. And from Graphisoft’s perspective, why re-invent the wheel when there are already popular tools like SketchUp (which can directly connect to ArchiCAD through an add-on) being used for conceptual design? Whether or not BIM applications should include conceptual massing capability continues to be debatable—there will always be those who prefer to have them in-house within the BIM application, while others would prefer to use the more extensive, intuitive, and fluid modeling features of external specialty tools like SketchUp or Bonzai3D and then import the massing model into a BIM application for further development. The lack of dedicated conceptual design tools within ArchiCAD will certainly be seen as a limitation by the former, while the latter would brush it aside and instead revel in the fact that ArchiCAD now lets you create BIM elements in any imaginable form.
It is also important to put ArchiCAD’s new form-making capabilities in the context of tools such as Bentley’s GenerativeComponents or Digital Project (described in detail in the BIM Evaluation Study Report), which are not only capable of creating sophisticated forms but also driving their generation through the use of parameters, so that modifications can be made to them by simply changing the parameter values without the need to remodel the form. From that perspective, ArchiCAD’s Shell tool is less sophisticated, as any changes required have to be made directly to the form rather than through driving parameters or through the propagation of changes made to the spatial configuration that the shell form is modeled on top of. Of course, GenerativeComponents and even Digital Project are far too complex for most architectural users, but still, it is important to keep this caveat regarding ArchiCAD’s new form-making capabilities in mind. Also, it should be noted that ArchiCAD does include GDL, an object scripting language that allows users to literally program any form mathematically imaginable, so the option is available for those are interested—it is just not directly available in the Shell tool.
Another key limitation in the application that continues to persist is the lack of an associative option for editing basic building elements which would maintain their relationships when modifications are made. While associativity has been nicely implemented for the new roof forms, even if they are complex, it is still annoying that walls, for example, have to be selected with a marquee and then “stretched” in order to maintain the connections between them. This is such a basic feature in most BIM tools (it is available even in Vectorworks Architect, as described in its recent review) that not having it in ArchiCAD makes it stick out like a sore thumb. Graphisoft needs to rethink its conservative approach to associativity, get back to the drawing board, and overhaul many of its traditional tools so that they behave in a more modern and intelligent fashion, not only to keep up with other BIM applications but also to enable more fluidity in modeling and editing in ArchiCAD. It would also be nice to make the application capable of opening multiple projects without requiring the user to open multiple instances of ArchiCAD, as it still the case.
The product documentation of the application continues to be stellar, with the new release especially well supported by a large number of videos online that explain the key features in great detail. There was a video for practically every new feature that I wanted to know about! The new 3D interface enhancements were amazing both in their range and depth, making it as easy to work in 3D in ArchiCAD as in 3D modeling applications such as form.Z. The new Roof tool is extremely powerful, and the ability to add to or cut portions from a complex roof with just a single click of the Magic Wand tool was incredible. It was also good to see the dedicated support for renovation projects, and the simple and intuitive manner in which it has been implemented. ArchiCAD does not have point cloud support yet which is now available in both of its key competitors, so it does have some catching up to do on functionality that is seen as important for renovation projects. But hopefully, once it does, it can again jump ahead of its competitors and find a way to convert point cloud data directly to BIM objects—which is what the industry really needs!
Overall, ArchiCAD continues to remain a very impressive BIM application that takes on specific themes in different releases and tackles them very comprehensively, keeping it ahead of its competitors in several aspects. It is by no means the “best” BIM application in all aspects, but ArchiCAD users who have adopted it as their BIM application of choice will be very pleased with the critical new capabilities that the latest release has made available to them.
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 firstname.lastname@example.org.
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