We elaborate on most of these topics throughout the remainder of this book. Using real-world examples, we illustrate a variety of techniques to visualize, analyze, and strategize using Revit.
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.
Figure 1.11 The effort curves in the design and construction industry
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.
Figure 1.12 BIM provides the most leverage when it is implemented early in the design.
Source: Based on a graphic created by Lee Miller, HOK
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.
The role of the architect is to generate the design intent and manage the technical issues of the project. As the model is being created, you will naturally have to solve issues like constructability and wall types and managing the program of spatial and equipment requirements, as well as other issues involving code compliance and client relationships. This role will be the one applying standards to the project (as in wall types, keynotes, and so on) and organizing the document set. This role will need to be present on the project from the beginning to ensure consistency of the virtual building creation and isn’t necessarily limited to only one person. This role also might or might not be a “designer.” Although it is possible to do early design in Revit software, many project teams prefer to use other tools such as SketchUp or even a pencil and tracing paper. The job of the architect is steering the creation of the building within the Revit environment. This role includes the following tasks:
● Leading the creation of architectural elements and building from within the model
● Designing around code requirements and other building logistics
● Constructability and detailing aspects of the design
The role of the modeler – in some firms referred to as the BIM coordinator – is to create and manage the 3D families and detail components needed in the project, which include all the parametric families for things such as windows, doors, casework, wall types, stairs, railings, furnishings, and so on. Typically, this role is the responsibility of less-experienced staff who might not be able to fulfill the role of architect. This role tends to have longer periods of undisturbed time, making it better suited to deal with some of the longer, more involved tasks in modeling content. Finally, it also tends to have some familiarity with modeling applications from academia or prior work experience. The modeler might not have worked with Revit software directly but possibly with 3ds Max software or Rhino. This role includes the following tasks:
● Creating model content and families
● Creating drafting components
● Managing system families within the project
The role of the drafter is to create sheets and embellish associated views with annotations or other 2D content. The drafter is responsible for the bulk of the work needed to document the project. In earlier stages of the project, this role is typically assumed by either the architect or the modeler, but as documentation progresses into later phases of design, this can quickly become the role of multiple people on a larger project. This role includes the following tasks:
● Keynoting
● Dimensioning
● Creating sheets and configuring views
● Creating schedules
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