Adobe Acrobat 3D

Late last month, Adobe announced their latest addition to the Acrobat family of products, Adobe Acrobat 3D, which now extends the visualization, publishing, and collaboration capabilities of the ubiquitous Adobe PDF format from 2D documents and drawings to 3D models as well. This can only be seen as a testament to the growing importance of 3D in design industries such as AEC (architecture, engineering, and construction) and manufacturing (including automotive, aerospace, machinery, and so on). Adobe Acrobat 3D is primarily targeted towards design engineering, technical publishing and creative professionals in these industries, and harnesses the reach of the free Adobe Reader to allow extended project teams working in 3D to collaborate and communicate quickly, securely and cost-effectively. Let's take a detailed look to see how it works.

Overview of Acrobat 3D

Adobe Acrobat 3D comes close to a year after the last Acrobat release, version 7.0 Professional. Recall from my review of that release that one of its most significant aspects, from an AEC perspective, was the ability to embed, view, and navigate 3D content in PDF files. This content, however, had to be a special format called U3D (Universal 3D), an open specification developed by the 3D Industry Forum that comprised of developers and corporate users of 3D graphics technology such as Intel, Adobe, Bentley Systems, Boeing, HP, and Right Hemisphere. From among AEC applications, only those from Bentley had the capability to export 3D models in the U3D format to PDF, and I showed an example of this in my review of Acrobat 7.0 Professional. Given this limitation, it was not surprising that 3D PDF didn't take off in a big way in AEC and was restricted primarily to Bentley users only (for example, by NBBJ, as mentioned in the recent AECbytes article, BIM Symposium at the University of Minnesota).

This limitation has been eliminated in Adobe Acrobat 3D to a large extent. It now has more ways to convert 3D models to the PDF format, including direct conversion from certain CAD file formats without the need of the authoring application, as well as a new creation method referred to as 3D capture, which can be used to create a 3D PDF file from other design applications that may not be directly supported. (The list of applications that are directly supported at this point is admittedly much larger for the manufacturing industry than for AEC, and includes CATIA, Pro/ENGINEER, and SolidWorks, among others.) The set of navigation tools that was introduced in Acrobat 7.0 Professional for navigating 3D content has been expanded in Acrobat 3D to include multiple display modes, the ability to create dynamic cross sections, and the display of a "model tree" which allows the visibility of different parts of the model to be manipulated as required. The application also comes with an associated utility called Acrobat 3D Toolkit, which allows the 3D content in the PDF file to be enhanced by editing lighting, adding textures and materials, and creating animations.

When enabled by Acrobat 3D, extended team members, consultants, and clients can then use the latest version, 7.0.7, of the free Adobe Reader application to review and add comments directly onto the 3D content embedded within the Adobe PDF file, without the need to have the original authoring application or any other CAD viewer. This version is already available for download from the Adobe website. If someone has an earlier version of Adobe Reader and is sent an "enabled" PDF file by someone using Acrobat 3D, the Adobe Reader user will be prompted upon trying to launch the document to download the latest version of the product.

Acrobat 3D also allows 3D models of the supported file formats to be directly inserted into Microsoft Word, Excel and PowerPoint files, so that when these files are published into the PDF format, they include the required interactive 3D content alongside traditional text-based and drawing-based content. While this capability is more useful for technical publishing and creative professionals creating brochures, catalogues, training content, operations manuals, and so on, it can also be used in AEC for creating presentation or construction drawings that include interactive 3D content for better explaining different aspects and details of a building. As with 2D content in PDF, the 3D content is compacted, so that the file size of a PDF file containing a 3D model would be substantially smaller than that of the original 3D authoring application.

Acrobat 3D joins the Acrobat family that includes Acrobat 7.0 Professional, Acrobat 7.0 Standard and Acrobat 7.0 Elements (see the difference between the Professional, Standard, and Elements versions in my review of Acrobat 6.0 Professional). While Acrobat 3D does not supersede Acrobat 7.0 Professional—which would still be the version of choice for those who don't need the 3D capability—it does include all of the functionality of Acrobat 7.0 Professional described in my review, including the ability to publish multiple layouts in AutoCAD as a multi-page PDF, ability to export PDF comments and markups back into the original authoring AutoCAD file, automatic scale embedding in the PDF so that manual scale calibration is no longer needed for measuring, new Callout and Dimensioning markup tools, and several other enhancements related to PDF creation, interface, organizing, designing forms, and security.

Getting 3D Content Into Acrobat 3D

Acrobat 3D allows 3D content to be published as Adobe PDF in three different ways, two of which are similar. Files that are in directly supported formats—which include 3DS, DXF, MAX, DGN, IGES, 3DM, VRML, and OBJ—can simply be dragged and dropped into Acrobat 3D. Alternately, you can right-click on them and select the "Convert to Adobe PDF' command from the context menu that appears. Most AEC users, therefore, with the exception of those working in MicroStation, would have to export their 3D models into one of these file formats to be able to import into Acrobat 3D using one of the above two methods. Figure 1 shows a sample Revit Building file brought into Acrobat 3D by exporting it first to MicroStation's DGN format.

There is also a third, more direct way for AEC users to get 3D content into Acrobat 3D from those CAD and BIM applications that support the OpenGL rendering mode. This is through the built-in 3D Capture utility, based on an OpenGL model capture technology developed by a French company, OKYZ, that Adobe acquired in December 2004. It allows users to quickly capture a 3D file displayed on screen in OpenGL mode and convert it to Adobe PDF. The use of the 3D Capture utility to capture a SketchUp model is illustrated in Figure 2. It involves first launching SketchUp, then Acrobat 3D, and selecting the "From 3D Capture" option under "Create PDF." A dialog box appears to notify that Acrobat 3D has recognized SketchUp. This needs to be done only once for any design application. When you now quit and relaunch SketchUp, you can simply use the Print Screen button to capture the SketchUp 3D model that is displayed on the screen. It is automatically sent to Acrobat 3D, and you also have the option of adjusting the capture settings before the model is displayed.

The 3D screen capture technology works with most applications commonly used in AEC, including AutoCAD, Autodesk Architectural Desktop (ADT), Autodesk Revit, form·Z, and so on. For some of these applications, some of the default settings need to be adjusted for the screen capture to work, either in Acrobat 3D or in the authoring application. For example, in AutoCAD or ADT, you have to access the System properties in the Options dialog, and under the Properties of the Current 3D Graphics Display, you have to enable Hardware Acceleration with wopengl8.hdi selected as the driver (see Figure 3-a). For Revit, on the other hand, no changes are required in its settings; however, the settings in Acrobat 3D for 3D capture from Revit have to be specified as shown in Figure 3-b. The 3D capture from Revit, for the same file shown in Figure 1, is illustrated in Figure 3-c, obtained after making the correct settings. A complete list of the required settings for 3D capture from various applications is given in this document on Adobe's Support website. If it is important to have the model to scale in the PDF file, the scale information must be defined during creation from 3D capture, otherwise default measurements are used.

There is yet another method to bring a 3D file of a specified format that is not directly supported into Acrobat 3D. A good example of this is DWG. While both AutoCAD and ADT files can be brought in through 3D Capture, or by saving as DXF which is directly supported, it can sometimes help to go through an additional step which involves the use of the Acrobat 3D Toolkit, a separate but associated application that is installed along with Acrobat 3D. This application allows advanced editing of a 3D model embedded in Acrobat 3D, and we will look at this capability in more detail in the next section. Let's look at 3D PDF creation, for which the Acrobat 3D Toolkit provides another avenue. It can directly import certain file formats such as DWG that are not supported by Acrobat 3D. (For a full list of the formats supported by both applications, see this Adobe support document.) Once you open up that file in the Toolkit, you can then save it as a U3D file, which is directly supported by Acrobat 3D and which can also be directly inserted into Microsoft Office documents to created PDFs combining 2D and 3D content. The advantage of importing through the 3D toolkit and then inserting into Acrobat 3D as opposed to doing a screen capture is that more information about the objects gets preserved using the former method. Thus, while a screen capture only captures geometrical information, importing a file into the 3D toolkit preserves some additional information such as layers and object names. It also preserves dimensional information, as well as material and texture information more accurately than a 3D capture. This is illustrated in Figure 4, which shows the same SketchUp file shown in Figure 2, imported into the Acrobat 3D Toolkit by exporting it first from SketchUp as a 3DS file.

It must be noted, however, that non-graphical and non-material attributes of objects, such as the U-value of a wall or the fire rating of a door—information that will usually be captured in a BIM model—is currently not captured in the 3D PDF format, regardless of which of the above methods is used for bringing the file into Acrobat 3D.

Working with 3D Content

Once you have got the required 3D content into Acrobat 3D using any of the methods described above, it can be visualized and manipulated in different ways. To start with, let's look at the enhancements that have been made in the 3D toolbar. Recall that the tools in Acrobat 7.0 Professional for working with 3D content included zoom, pan, rotate, adjusting lighting, switching to different predefined views, changing the background color, and hiding, showing, and isolating selecting elements. Some significant new capabilities have been added to this toolbar in Acrobat 3D. A Model Tree option allows you to see how the model is broken down into its various parts, and gives you the option of turning the visibility of each part off or on, as shown in Figure 5. You can create and save different views that you can return to, right below the model tree information. Some basic information about the model is also listed. Another toolbar option gives you the choice of several different display modes including Solid, Transparent, Shaded Illustration, and so on. And finally, another significant new capability is the ability to see a cross section of the model and dynamically adjust the alignment, offset, and tilt of the cutting plane, as shown in Figure 5. You can also save the cross sectional views for quick visualization later, as well as generate cross sectional views with the camera aligned with the cutting plane, allowing plans and sections of the building to be saved for quick reference.

For project collaboration between an extended team using Adobe PDF, the commenting, markup, and review tools in Acrobat 3D are the same as in Acrobat 7.0 Professional, with the added ability to add view-specific comments to the 3D content, as shown in Figure 6. All comments added in a particular view get saved with a view, and can be reviewed by others accessing that document. Also, when enabled by Acrobat 3D, users of the free Adobe Reader can also add their comments directly on 3D objects and 2D content within the Adobe PDF files. Extended team members can define multiple cross-sections of a 3D model illustrating plans and sections to facilitate the review process. Unlike 2D comments and markups on a PDF file generated from AutoCAD which can be round-tripped back to AutoCAD, comments and markups on a 3D model cannot, however, be exported back to the original 3D authoring application.

If you right-click on a 3D model in Acrobat 3D, you can select the option for editing it in the Acrobat 3D toolkit. This will launch the same application shown in Figure 4, where you can make changes to the model—such as textures, shading and materials—and add animation, views and lights, without returning to the original CAD file. You can also output high-quality 2D graphics from the 3D model for use in documentation. An Optimize Geometry option is also available to simplify 3D models that are complex and weighty by removing duplicate faces, duplicate materials, internal parts, and so on.

And finally, those who are adept with programming can use Javascript to add to or limit the functionality available in a PDF. Javascript can be added to the file during the creation process or after the PDF has already been created. Examples of Javascript enhancements to 3D content in Acrobat 3D include adding a grid to the PDF file, limiting rotating to a specified axis only, and so on.

Analysis and Conclusions

The ability to capture and embed 3D design information in a PDF file and subsequently share it for collaboration and review—for free—is certain to be welcomed by AEC professionals as 3D takes off in the industry. In my last review of Acrobat 7.0 Professional, where 3D had just been introduced, I commented that Acrobat needed to continue to broaden its focus from 2D to 3D, and that it would be interesting to see how much further the PDF format could go. I hadn't expected such a giant technological leap in just a year! The ability to capture 3D model information from an open application right from the screen and convert it to PDF on the fly is a very powerful one, and constitutes a critical breakthrough for Acrobat and PDF. It will continue to maintain PDF's current stature as one of the most ubiquitous and compelling options for electronic publishing in the AEC industry.

At the same time, it is important to recognize that since the 3D content in a PDF file does not retain its non-geometric properties, it does lose a part of its "intelligence." Thus, it cannot supplant the use of specialized design review and design checking applications such as NavisWorks and Solibri Model Checker, which are being increasingly used to detect conflicts between the different disciplinary models of a building. And, of course, Autodesk continues to forge ahead with its own electronic publishing format, DWF, which can capture attribute information in both 2D and 3D and is now being used as the basis for developing applications such as quantity take-off and asset management, both by Autodesk as well as third-party developers. It seems as though Adobe PDF is moving ahead with developing unique 3D capabilities of its own, and as it does so, it is differentiating itself more strongly in scope and purpose from other electronic publishing solutions. It will likely remain the most popular way to electronically capture and share documents comprising both 2D and 3D information—culled from practically any kind of software application under the sun.

There is, however, still some scope for improvement in Acrobat 3D, at least from an AEC perspective. Since most of the commonly used file formats are not directly supported, users will have to spend some time understanding how 3D capture works and configuring their settings for each of the individual design applications they are working with. The navigation capabilities for the 3D content need to be improved to make it easier to rotate views about the Z axis so that the building continues to stand "straight up" when rotated. Currently, this can be done only using Javascript by those who know scripting. Also, at a street price of $995, Acrobat 3D is more than twice the price of Adobe Acrobat 7.0 Professional and it remains to be seen how many users will make the switch. It certainly doesn't need to replace all the seats of Acrobat 7.0 Professional being used in an organization; firms can get by with upgrading only for a few users commissioned with the task of creating the 3D PDF files for review. Acrobat 3D is going to gain much more initial traction in the manufacturing industry, which has already embraced 3D fully, and which will find it tremendously useful to capture machine parts, assemblies, and so on in PDF format (see Figure 7). Larger projects like buildings are not as amenable to being usefully captured and presented in 3D PDF format compared to smaller parts such as machinery.

But the AEC industry is an important market for Adobe's Acrobat product line-up, experiencing a 70% growth over the last year. Hopefully, future versions of Acrobat 3D will provide more direct support for commonly used CAD and BIM applications in AEC, and possibly capture more non-graphical object attribute data to make for a richer 3D PDF file, which in turn might spawn a whole new generation of PDF-based applications for different aspects of design, construction, and operation. The possibilities are indeed limitless.

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 lachmi@aecbytes.com.