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Building Design

1-2-3 REVIT: Publish BIMs in DWF

6 Oct, 2006 By: AIA ,Rick Rundell

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Share your designs safely and quickly with your design team, clients and contractors.

Several of my articles have focused on how BIMs (building information models) can be shared with distributed design teams -- using Revit Worksharing and across a WAN, for instance. But what happens when design data must be shared outside the design team with clients, contractors, city planners and other constituents in the review cycle that aren't Revit users -- or even CAD users? This month's article focuses on DWF, a tool that extends the BIM design process and facilitates the sharing of consistent, coordinated information that comes from a BIM.

About DWF
Studies suggest that the ratio of people needing to use design information, versus those who create it, is about 10 to 1 . Autodesk created DWF in 1996 for those information consumers. Its function is to distribute and communicate design information to anyone who needs to view, review, print and access it for any purpose -- without losing critical data, and without these users needing to understand, or even possess, the native design software. A free DWF Viewer is available from Autodesk, and to date more than 12 million people have downloaded it.

DWFs are not the original design model and they can't be edited -- they can only be marked up. Sometimes referred to as light geometry, DWF files can carry very large data sets in a very compressed format, much smaller than the original design files. A gigabyte-sized design file can be compressed to a DWF file that's small enough to e-mail, making the Internet a viable replacement for overnight mail or couriers.

The ability to publish to DWF is embedded in almost all Autodesk design applications, including Revit. Revit users can publish their design data, including multisheet drawing sets and 3D models, in a single print-ready, password-protected DWF file.

How do imaging formats like TIFF, JPEG, or PDF compare to DWF? They don't capture the intelligence in a design model because they're basically 2D images of 3D models and cannot share specific design information. In the case of Acrobat 3D, the images only capture the visual aspects of the model, and don't include the metadata available as part of the DWF model.

BIM and DWF
As a publishing format, DWF files are not BIMs. Instead, they are a mechanism for publishing information from the BIM and sharing that information with extended teams. In fact, the coordinated, consistent and reliable information delivered by BIM is the foundation for the value DWF can deliver in a building design workflow.

With DWF files, Revit models can be published and shared with non-Revit users, including general contractors (early on in the process, during constructability reviews), clients (for visualization purposes), subcontractors (for soliciting pricing information) and so on. They can also be used to transmit information to other applications, such as facilities management or cost estimating. For more on cost estimating see last month's article.

The Revit user controls how a model is published to DWF and can control what information is shared. For example, you can publish a DWF file that contains only the electrical drawing set and another with the electrical model components together with the architectural underlay.

As I mentioned earlier, DWFs are published models that can't be edited, but they can be queried. They're accurate representations of a model and DWF viewers can measure distances, areas and angles and snap to model geometry. For example, a building inspector can measure the area of a room or the distance between two electrical wall sockets.

Properties associated with building components are also transferred to the DWF. In the DWF Viewer, the user selects an object, such as a door, and can see all the properties associated with that object: the door size, its fire rating, the frame material, associated hinges and so forth. In another example, perhaps it's a custom-order door requested by the client. The architect can add specification information to the Revit model, such as acceptable manufacturers and part numbers, etc. All this information is transferred via DWF, which is ultimately viewable by the builder for estimating without any information being lost along the way.

The DWF Viewer provides powerful 3D viewing capabilities as well, letting you navigate through saved 3D views and specify the presentation mode: shaded, edges only or shaded with edges. The model can be rotated around one axis or spun about in any direction. You can also isolate, cross-section and hide building model components.

Beyond these viewing capabilities, DWF is also at the core of the Autodesk Design Review software (formerly DWF Composer), a completely digital way for a team to review, markup and track changes to sheet sets and building models.

Digital Design Review
Autodesk Design Review facilitates electronic review cycles by taking the BIM published to digital DWF files from Revit and tracking redlines to those DWFs. By minimizing paper, errors are reduced and the risk of inaccurate or out-of-date information being used during the review process is minimized. Autodesk Design Review lets reviewers markup the DWF, making their comments and notes in the context of the design while automatically tracking the markups. In this fashion, the input from all participants in the review cycle is added to the BIM and communicated directly back to the original designer. Additional information can also be added to the DWF, such as JPG renderings, Word-based specifications, project timelines and the like. DWF becomes the container for that information, distributing it to participants in the design review process as needed. Let's examine one specific example of a company sharing design data from a BIM: a construction company using BIM to better communicate the built environment.

Build Smarter, Build Better
J.E. Dunn Rocky Mountain, part of J.E. Dunn Construction, is a commercial general contractor with expertise in construction management, program management and design/build projects. With offices in Denver and Colorado Springs, J.E. Dunn Rocky Mountain has more than 270 employees in the region. In 2005, it placed more than $205 million of work, with roughly $280 million under contract for 2006. J.E. Dunn Rocky Mountain uses Revit to enhance its pre-construction and estimating services, automated field layout for its concrete, construction visualization, and rough carpentry work and subcontractor coordination. It typically receives drawings from the design architect and then creates its own construction models within Revit. A Revit user since 2005, the company uses DWFs to communicate building data in two opposite directions -- with its design firms and with its field construction personnel.

To enhance the level of understanding of the project that the company is building and reduce construction mistakes, it often publishes 3D views of the Revit model to share with construction personnel on site. Rodd Merchant, quality assurance and BIM manager, gives this example: "We'll have a foreman on a job site who's getting ready to pour a 60-foot section of wall. To help him understand exactly what he's building, we publish just that wall with all of its components to DWF, and then e-mail the file to the foreman. He can look at it on his laptop in the construction trailer and really see it -- spin it around, peel back sections and query components for property information."

DWF also increases the level of communication with designers and speeds up the RFI (request for information) process. For example, if an interference conflict is found in a construction model, rather than sending paper to the design team, builders now publish the pertinent part of the model to DWF, use Autodesk Design Review to highlight and annotate the conflict and send that RFI sketch off to the architect for a response. The digital process speeds up the effort on each end and gives the architect a clearer understanding of the RFI, producing an extremely quick turnaround time (sometimes just minutes, instead of what used to be days) and reducing the number of change orders.

"The richness of the Revit BIM and its visualization capabilities lets us gain a much better understanding of what we're building," states Merchant. "Using DWF coupled with Autodesk Design Review allows us to quickly and easily share that understanding with all the constituents in the building process: the architects who are designing the building, the client who's paying for the building and the workers on site who are actually building the building."

Faster Review Cycles
Our global economy, fierce competition in the building industry and increasingly complex building processes are driving firms to seek more efficient and effective methods of collaboration, both inside and outside the firm. Publishing BIMs using DWF is a better way to communicate a building design and can lead to faster review cycles, more complete RFI processes and a decrease in engineering change orders. It's all about getting the right information to the right people and accelerating the design review process.