Source: HOK
By adding materiality to the BIM elements, you can begin to explore the space in color and light, creating photorealistic renderings of portions of the building design. These highly literal images convey information about both intent and content of the design. Iterations at this level are limited only by processing power. The photorealism allows for an almost lifelike exploration of color and light qualities within a built space even to the extent of allowing analytic brightness calculations to reveal the exact levels of light within a space.
The next logical step is taking these elements and adding the element of time. In Figure 1.8, you can see a still image taken from a phasing animation (commonly referred to as a 4D simulation) of a project. Not only do these simulations convey time and movement through space, but they also have the ability to demonstrate how the building will react or perform under real lighting and atmospheric conditions. All of this fosters a more complete understanding of the constructability and performance of a project before it is realized.
Figure 1.8 A still from an animation showing accurate physical conditions for the project
Source: HOK
BIM AS A SINGLE SOURCE MODEL
In the early 2000s, if you wanted to create a rendering, a physical model, a daylighting model, an energy model, and an animation, you would have had to create five separate models and use five different pieces of software. There was no ability to reuse model geometry and data between model uses. One of the key uses of BIM is the opportunity to repurpose the model for a variety of visualizations. This not only allows you to not have to re-create geometry between uses, but also ensures you’re using the most current information in each visualization because it all comes from the same source. As the capacity of cloud rendering and analysis grows, the feedback will no longer need to process locally and you’ll be able to receive feedback faster.
As with visualization, the authoring environment of a BIM platform isn’t necessarily the most efficient one on which to perform analysis. Although you can create some rendering and animations within Revit, a host of other applications are specifically designed to capitalize on a computer’s RAM and processing power to minimize the time it takes to create such media. Analysis is much the same way – although some basic analysis is possible using Revit, other applications are much more robust and can create more accurate results. The real value in BIM beyond design documentation is the interoperability of model geometry and metadata between applications. Consider energy modeling as an example. In Figure 1.9, we’re comparing three energy-modeling applications: A, B, and C. In the figure, the darkest blue bar reflects the time it takes to either import model geometry into the analysis package or redraw the design with the analysis package. The lighter blue bar reflects the amount of time needed to add data not within Revit, such as loads, zoning, and so on. The lightest bar represents the time it takes to perform the analysis once all the information is in place.
Figure 1.9 BIM environmental analysis time comparison
In A and B, we modeled the project in Revit but were unable to use the model geometry in the analysis package. This caused the re-creation of the design within the analysis tool and also required time to coordinate and maintain the design and its iterations between the two models. In application C, you can see we were able to import Revit model geometry directly into the analysis package, saving nearly 50 percent of the time needed to create and run the full analysis. Using this workflow, you can bring analysis to more projects, perform more iterations, or do the analysis in half the time.
The same workflow is true for daylighting (Figure 1.10) and other types of building performance analysis. With the ability to repurpose the Revit model geometry, we are able to move away from anecdotal or prescriptive design solutions and begin to rely on calculated results. Using Revit also ensures consistency because the model is the sole source for design geometry.
Figure 1.10 Daylighting overlay from Autodesk® 3ds Max® Design software
Building analysis can reach beyond just the design phase and into the whole building life cycle. Once the building has been constructed, the use of BIM doesn’t need to end. More advanced facilities management systems support tracking – and thereby trending – building use over time. By trending building use, you can begin to predict usage patterns and help anticipate future uses such as energy consumption or future expansion. This strategy can help you become more proactive with maintenance and equipment replacement because you will be able to “see” how equipment performance begins to degrade over time. Trending will also aid you in providing a more comfortable environment for building occupants by understanding historic use patterns and allowing you to keep the building tuned for optimized energy performance.
To maximize your investment in a BIM-based workflow, it’s necessary to apply a bit of planning. As in design, a well-planned and flexible implementation is paramount to a project’s success. By identifying goals on a project early on in the process, it allows BIM to be implemented efficiently to reach those objectives. An effective strategy answers three key questions about a project:
● What processes do we need to employ to achieve our project goals?
● Who are the key team members to implement those processes?
● How will we support the people and processes with technology or applications?
Ask these questions of your firm as a whole so you can collectively work toward expertise in a given area, be that sustainable design or construction or something else. Ask the same questions of an individual project as well so you can begin building the model in early stages for potential downstream uses. In both cases (firm-wide or project-based), processes will need to change to meet the goals you’ve established. Modeling techniques and workflows will need to be established. Analysis-based BIM requires different constraints and requirements than a model used for documentation or clash detection. If you’re taking the model into facilities management, you’ll need to add a lot of metadata about equipment but at a lower level of detail than if you were performing daylighting studies. Applying a new level of model integrity during a design phase can be a frustrating and time-consuming endeavor. Regardless of the goal, setting and understanding those goals early on in the project process is a prerequisite for success.
Focusing Your Investment in BIM
One of the common assumptions is that larger firms have a better opportunity than smaller firms in their capacity to take on new technologies or innovate. Although larger firms might have a broader pool of resources, much of the investment is proportionally the same. We have been fortunate enough to help a number of firms implement Revit over the years, and each has looked to focus on different capabilities of the software that best express their individual direction. Although these firms have varied in size and individual desire to take on risk, their investments have all been relatively equal. From big firms to small, the investment ratio consistently equates to about 1 percent of the size of the firm. If you consider a 1,000-person firm, that equals about 10 full-time people; however, scale that down to a 10-person firm, and that becomes 1 person’s time for five weeks.
The key to optimizing this 1-percent investment is focusing your firm’s energy and resources on the most appropriate implementation objectives.
Identifying the importance of visualization, analysis, and strategy to your process will help guide you in selecting areas of implementation within your own practice. If your investment (regardless of scale) is focused and well planned, it will yield strong results. When choosing areas of implementation or how much focus to give