Visualizing

Creating documentation using BIM gives you the added advantage of being able to visualize the project in 3D. Although this was initially conceived as one of the “low-hanging fruits” of a BIM workflow, this benefit has led to an explosion of 3D graphics—perspectives, wire frames, cloud renderings, and animations—within the industry as a means to communicate design between stakeholders on a project.

This digital creation of the project has given us a variety of tools to communicate aspects of the project. It becomes “architecture in miniature,” and we can take the model and create a seemingly unlimited number of interior and exterior visualizations. The same model may be imported into a gaming engine for an interactive virtual experience. Clients no longer need to rely on the designer’s pre-established paths in a fly-through—they can virtually “walk” through the building at their own pace, exploring an endless variety of directions. The same model can then be turned into a physical manifestation either in part or in whole by the use of 3D printers (known as rapid prototyping), creating small models (Figure 1.4) in a fraction of the time it would take to build one by hand. Many types of visualization are currently possible with BIM.

If we consider a complete spectrum of representations, from tabular data to 2D documentation and then to 3D visualization, tremendous opportunities exist to transform the notion of traditional design deliverables. Schedules give you instantaneous reports on component quantities and space usage, whereas plans, sections, and elevations afford you the flexibility to customize their display using the information embedded in the modeled elements. For example, the plan in Figure 1.5 shows how color fills can be automatically applied to illustrate space usage by department.

Expanding 2D documentation to include 3D imagery also gives you the ability to clearly communicate the intent of more complex designs. It may even have a positive effect on construction by transcending possible language barriers with illustrative documentation rather than cryptic details and notations. Figure 1.6 shows a basic example of a drawing sheet composed of both 2D and 3D views generated directly from the project model.

The obvious benefit to creating a complete digital model of your building project is the ability to generate a wide variety of 3D images for presentation. These images are used to not only describe design intent but also to illustrate ideas about proportion, form, space, and functional relationships. The ease at which these kinds of views can be mass-produced makes the rendered perspective more of a commodity. In some instances, as shown in the left image of Figure 1.7, materiality may be removed to focus on the building form and element adjacencies. The same model is used again for a final photorealistic rendering, as shown in the right image of Figure 1.7.

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.

Analyzing

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.

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.

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.

Strategizing

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.

Staffing for BIM

As you rethink the process of design and documentation, one of the fundamental changes you will need to address is staffing. A common misconception of project management when teams are first moving from CAD to BIM is that staffing the project will be the same in both workflows. This couldn’t be further from the truth because when the workflow changes, staffing allocations, the time to complete tasks, and the percentage of work by phase are all affected as a result of the changes.

Several years ago, Patrick MacLeamy, FAIA, set out to illustrate the fundamental benefit to more informed design that happened to be a by-product of building information modeling. The graph, which has come to be known as the MacLeamy Curve (Figure 1.11), is not intended to imply a simple shift in labor earlier in the design process; rather, it stresses the importance of being able to make higher-value decisions before it becomes too difficult to make changes to a design. The x-axis of the chart represents project phases from conceptual design through occupancy, whereas the y-axis represents the amount of effort in each phase.

Another way to think about this shift is as a diagram of leverage, as shown in Figure 1.12. Implementing BIM in earlier phases of a project gives you the greatest opportunity to add value to the overall compilation of building information delivered for a facility. When you begin BIM earlier, you may need to increase staff to build a better model or to perform energy analysis or preliminary quantity takeoffs; however, using a better tool like Revit software will not necessarily translate to the same labor used in a CAD-based project. You will find how this affects your team effort after a few BIM projects.

Understanding Project Roles

With such a significant change in the effort behind a BIM-based project workflow, it’s also important to understand how this change affects the various roles and responsibilities for the project team. Project managers need to be able to predict staffing and time to complete tasks throughout the project phases and have relied on past precedent of staff and project types to do this. Because a BIM-based project can significantly alter the project workflow, many of the historic timetables for task completion are no longer valid. However, a BIM-based project can be broken down into a few primary roles that will allow you some level of predictability throughout the various project phases. Although the specific effort and staffing will vary between offices (and even projects), there are some general roles that will need to be accounted for on every project.

Here are three primary roles that should be considered on every BIM project:

Architect  Generates design intent and coordinates issues such as material, code compliance, wall type, spatial program, and so on.

Modeler  Creates 2D or 3D content that directly represents the design intent.

Drafter  Works with annotations, sheet layout, view creation, and detail creation.

These roles represent efforts and general tasks that you need to take into account on any Revit project. On a large project, these roles could also represent individual people, whereas on a smaller project they might be all the same person fulfilling multiple roles. We’ll now explore each of these in more detail and discuss how these roles affect the project workflow.

Establishing a BIM Execution Plan

To optimize your results with BIM, it’s important to start with the end in mind. Although a lot of tasks are possible with a BIM model before you draw your first wall, you will want to create a BIM execution plan. We go into more detail about creating these plans and some resources for them in Chapter 6, “Working with Consultants,” but essentially a BIM plan helps to drive the direction of the modeling effort and modeling outcomes. Will your project need to add parameters for energy modeling? Daylighting? Does the owner have expectations for a model deliverable? How much does everyone model without being too much? All of those possibilities and more are explored and documented in a BIM execution plan. It gives the project team a definitive outcome to model toward.

The BIM plan will also help address which team members you’ll need at which phases of the design. For instance, at the inception of a project design, a modeling role will be of the best use. This person can help create building form, add conceptual content, and get the massing for the building established. If you’re using the conceptual modeling tools (covered in Chapter 8, “Advanced Modeling and Massing”), the modeler can even do some early sustainable design calculations (covered in Chapter 9, “Conceptual Design and Design Analysis”).

Once the project begins to take a more established form and you complete conceptual design, you’ll need an architect role to step into the project. As in a typical project, you’ll have to mold the form into a building by applying materials, applying wall types, and validating spatial requirements and the owner’s program.

During schematic design, you’ll need to include the role of the drafter to begin laying out sheets and creating views. These sheets and views don’t have to be for a construction document set as of yet, but you’ll need to establish views for any schematic design submittals. If these views are set up properly, they can be reused later for design development and construction document submittals as the model continues to gain a greater level of detail.

You should avoid adding staff to your project during the construction documentation phase. In a BIM/Revit workflow, this can sometimes cause more problems than it solves and slow down the team rather than get work done faster.

Another proven technique of managing larger Revit projects is to assign work according to elements of the building rather than by drawing a series. For example, one person would be responsible for building enclosures and another for structure, interior partitions, furniture, vertical circulation, and so on. This strategy encourages each team member to develop their portion of the design more collaboratively because the modeling for each component must be coordinated with the surrounding systems.

Even though your team won’t be assigned work through a series of sheets, each person should be tasked with overseeing each sheet series. The annotation related to each building system is the responsibility of the respectively assigned team member, but someone else will be responsible for reviewing each series of sheets to ensure that they are appropriately maintained for presentation or distribution. On smaller projects, the project architect would likely be the person supervising the entire sheet set.

This dual responsibility is an important aspect of team management that will keep your BIM projects on track. Spending the majority of time working in the model and thus neglecting the preparation of properly annotated sheet views becomes very alluring.