Using Building Information Modeling for Architectural Drawings

BIM tools can improve professional practice and drawing quality without any compromise

By Peter J. Arsenault, FAIA, NCARB, LEED AP

Managing an architectural practice means, among other things, managing the process for providing services. That includes having capable people doing the work that needs to be done in a timely and efficient manner. It also means providing those people with the flexibility and freedom to produce creative work and innovative design. Each firm or workplace typically develops its own culture to achieve these management goals with direct influence coming from both the individuals involved in the firm and the tools that are employed to do the work. Finding and engaging the right people is a needed crucial activity, but so is identifying and using the best tools. In recent decades, firms have steadily abandoned hand-drawing tools for design and construction documents in favor of computerized tools to achieve better results. While two-dimensional CAD drawings have been the norm for some time now, three-dimensional computer models of buildings have been steadily growing in use in architectural practices around the world. For some, the computer software is simply an electronic means to produce visual elements of a drawing such as lines, shapes, forms, and text. For many others, it is a way to link the visual, three-dimensional components in a project to specific information about building systems, materials, products, and performance characteristics. As such, it is also a way to produce better-coordinated, higher-quality construction documents. This latter approach is the basis of building information modeling (BIM) and is emerging as the new norm for successful architectural practices.

What has driven the move toward BIM? For some, using this advanced technology is simply a logical evolution of the way the firm has been operating but allows a more consolidated, coordinated and time-efficient way of working. Others have have found that it allows architects to design with more creative freedom through better visualization at different stages of design. For still others, it has offered improved collaboration and coordination by multiple project stakeholders, thus reducing the potential for miscommunication, errors, or omissions in the final documents. In all cases, the quality of the documents produced has also been a major advantage. However, this three-dimensional, collaborative design and documentation software has not usurped the need to still produce printed, stamped construction drawings. Such stamped drawings are still expected from most owners, code officials, financial stakeholders, and construction contractors. The good news is that BIM can do that too. In fact, for firms that are fully embracing BIM, they are finding that producing documents of all types—from schematic through design development into construction documents and beyond—is done most effectively, efficiently, and with the best quality through the use of BIM software. Further, the firms and practitioners that are taking the time to fully understand and implement the full range of features found in BIM software are reaping multiple benefits related to new innovations in design, more efficient work processes, and better overall project (and firm) management.

In this course, we will look at some of the apects of successfully incorporating BIM into a professional design practice focused on versatility of design and quality output, plus review the experiences of some of the firms that are doing it.

Accepting the Output of BIM

In making the transition from other design and documentation methods to BIM, questions and uncertainty can arise since this may include a change in firm culture. Therefore, the first mindset that needs to be established is that the computerized building information model needs to be seen as the “single source of truth” throughout a project’s design process. In other design and documentation methods, there are commonly multiple sources of the truth for a project that are all coming together from different people and in different forms. That requires coordination at the very least and detailed review, interpretation, and integration at most. The use of a central building information model still allows all of those separate sources (i.e., people involved in the project) to do the things they need to in order to assess, analyze, and synthesize particular aspects of the design. But ultimately, when each person provides the design data, sizing, and product or material information related to their parts of the building, they are each contributing to this central, single source of up-to-date information. In so doing, they can also see how their part relates to the rest of the building and systems and respond accordingly.

One of the key aspects of BIM is that it is based on “objects” that represent the actual materials, products, and assemblies that make up a building. This means that a wall may still show up as lines in plan view, but in fact it is in the model as a three-dimensional wall with a defined width, length, height, and material makeup based on the attributes assigned to it. Similarly, discreet objects like windows, doors, or furnishings can be viewed two dimensionally but in fact are stored as three-dimensional objects with definable attributes such as size, shape, materials, finish, etc. All of these attributes for any part of the building can be identified as generic or “default” choices at the beginning of a project that can be modified, adjusted, updated, or changed completely at any time.

Using this object-based approach, the design team is in essence using BIM as a means not just to graphically represent different parts of a building but also to actually assemble and “build” it electronically in the model. In so doing, different options can be tried, substituted, updated, coordinated, etc. simply by making the edits or revisions as appropriate within the computer model. Those edits may be visually based, such as the size or shape of a building component, or they may be purely information based, such as a change in the specification or manufacturer’s data for a product or material. The point is that everyone benefits from working off of the same central model and accepting the information within it as the current representation of the project.

This approach doesn’t mean that only completely detailed information can go into the model. During early design stages, the information is typically still being developed, collected, researched, or analyzed. Therefore, it may be premature to include details that may or may not become part of the final design. In those cases, just some basic or default information can be provided that can be developed and updated later on as decisions are made. This approach allows for a firm’s typical design process to still take place, it just changes the place where all of the design information is stored to be in the central model. Of course, it is still possible to create several preliminary computer models representing different design schemes or concepts and then compare them, make adjustments as appropriate, and ultimately select a final concept to with which to move forward.

Using the Model for All Drawings

Part of the mindset of trusting a central model for a project and “building” it as the process moves along is to recognize that the 3-D model is also meant to be the basis for all 3-D views and 2-D drawings. That includes preliminary documents for schematic and design development purposes, renderings and presentation drawings, and ultimately construction documents. Some firms use other software besides BIM as an intermediary to create different drawings for different project phases. The obvious problem with that approach is the loss in efficiency since designs need to be drawn and re-drawn in different computer programs. Even if information is transferred between the two software programs, time is typically spent to verify that important data is transferred properly. Either way, producing drawings multiple times or transferring between programs can increases the risk of errors or omissions.

The better alternative is to select a BIM software program that allows the generation of all needed drawings directly from the central model. Firms that are doing this are benefitting the most since they recognize the full power and potential of BIM as a complete design and documentation tool. By capitalizing on the full capabilities of the software program, they are using it to their advantage to create early design “sketches.” conceptual 3-D views, simple or elaborate renderings, progress prints, and construction documents. This helps such firms achieve their overall management objectives and produce better outcomes.

It should be noted that in addition to a core BIM software program, there are also compatible specialty “add-on” programs available. These can be linked in to operate within the main program so that switching in and out of the primary software is not needed, thus saving time and still keeping everything in one place. There are a range of such specialties that may or may not be of interest to a firm so they can be evaluated accordingly. In some cases, a popular add-on may be acquired by the software developer and ultimately be incorporated directly as part of the overall program. That can make it even easier to use and boost the capabilities and accuracy of the software tool.

The People Factor

Any tool is only as good as the capabilities of the people who are using it, of course. In the architectural profession, computer-based design, including BIM, can be done by a variety of people with a variety of experience and skills. In some cases, it is a younger person who may be very adept at using computer technology but doesn’t yet have the experience of how buildings are successfully “put together.” In other cases, it may be a middle-aged or older person who has the design and construction experience but has not advanced their computer skills. In the ideal situation, it is a person who has the knowledge of how to design and construct buildings combined with the skills of using computers to do so. Indeed, many firms, small ones in particular, are achieving great success with experienced and skilled architects designing and managing projects directly in BIM. That means gone are the days of “red-lining” progress prints prepared by a CAD drafter—the designer, project manager, and the drafter can all be one person thanks to the substantial assistance of the computer. That has been a major productivity boost that has allowed many small firms to compete with larger ones on projects they wouldn’t otherwise have the capacity to take on.

Recognizing the variability of capabilities of different people, each firm manager or sole practitioner needs to not only assess the skills and experience of themselves or their people but also be proactive about addressing any shortcomings. Mentoring and balanced work assignments have often been used to effectively help younger professionals get the experience needed to better understand buildings. For computer skills, though, some degree of computer training and practice using the specific program is the common route followed. Even design professionals with good computer skills can benefit from such training to go beyond a basic level of familiarity with the software to a more complete understanding and fully functional level of use. In order to get there, firm principals need to place a value on the training, make it available (i.e., take advantage of in-person, online, or other training options available from software companies, local representatives, or third parties), and cover any nominal cost for it. Typically, firms that invest even a small amount in such training often find a substantial boost in productivity, helping to improve the overall productivity and financial performance of the firm.

Overall, with the proper mindset, the willingness to use BIM as the primary source of information through all phases of a project, and the appropriate level of training and support, BIM can become a means not only to better projects but also to the sustainability and longevity of the firm.

Levels of Development

One of the needed management aspects to address in the process of BIM development and quality control in drawings is the level of detail needed at each stage of design and into construction. Fortunately, there is an organization that is addressing this issue. Known as the BIMForum (www.bimformum.org), it is the not-for-profit United States chapter of buildingSMART International with a mission focused on improved BIM technology, collaboration, education, innovation, and open information exchange. According to the chapter, “Cosponsored by the Associated General Contractors of America (AGC) and the American Institute of Architects (AIA), BIMForum seeks to lead by example and synchronize with counterparts in all sectors of the industry to jointly develop best practices for virtual design and construction.”

A flagship publication of BIMForum is a fully collaborative document known as the Level of Development (LOD) Specification, with it’s latest release in September of 2018.¹ Having evolved over several years, this resource is “a reference that enables practitioners in the AEC Industry to specify and articulate with a high level of clarity the content and reliability of building information models (BIMs) at various stages in the design and construction process.” Coordinated with other industry standards, it “defines and illustrates characteristics of model elements of different building systems at different Levels of Development.” Essentially, it defines and standardizes how much detail is expected in a building information model at different stages of the design process. Therefore, if any project team member, including manufacturers, fabricators, or trades, are asked to supply their BIM information, they only need to ask “what Level of Development?” In this way, each person is providing the right amount of information to coordinate with the most current version of the larger computer model for the building.

The LOD Specification is based first on referring to building objects as “Model Elements,” which are eseentially the trade-based components of constructing any building. They are formatted by the familiar Uniformat or Omniclass specification sections (similar to Master Format) used by most spec writers (e.g., Divisions and Sections for sitework, concrete, metals, carpentry, finishes, etc.).² From there, five levels of detailing are described for each Model Element, identified by the numbers LOD 100, 200, 300, 350, and 400, as described further below.

LOD 100: This is the most basic of models where “the Model Elements may be graphically represented in the Model with a symbol or other generic representation but does not satisfy the requirements for LOD 200. Information related to the Model Element (i.e., cost per square foot, tonnage of HVAC, etc.) can be derived from other Model Elements.” This level of BIM is a starting point showing the existence of a component at a conceptual or schematic level. BIMForum points out that this level does not necessarily provide the shape, size, or precise location of any Model Elements; rather, “any information derived from LOD 100 elements must be considered approximate.”

LOD 200: At this level, basic data is attached to the Model Elements such that they are “graphically represented within the Model as a generic system, object, or assembly with approximate quantities, size, shape, location, and orientation.” As such, everything shown is still fairly generic but can be considered entering the traditional “Design Development” stage. Objects or elements are still considered as approximate “placeholders” in the model.

LOD 300: At this level, things are getting more specific and may be considered as entering the “Construction Documents” level of detail. At this point, the Model Elements are “graphically represented within the Model as a specific system, object, or assembly in terms of quantity, size, shape, location, and orientation.” While it is possible to link non-graphic information at any level (i.e., specification details, cost information, material data, etc.), it is likely to be attached to most Model Elements at this point.

LOD 350: This level is focused on coordination between elements or building systems. In this case, BIMForum comments, “Parts necessary for coordination of the element with nearby or attached elements are modeled. These parts will include such items as supports and connections. The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension call-outs.” This level of detail is, in essence, complete enough to represent 100 percent “Construction Documents” and a finished, coordinated building in most respects.

LOD 400: This is the full fabrication level equivalent to a shop drawing level of detail. It is worth noting that if trades and fabricators are identified during design so that this level of detail can be incorporated into the model before construction begins, then there will be no need to request or review shop drawings during the construction phase of a project. That creates the best possibility for a fully coordinated design ahead of time and can make a firm more efficient during the construction phase.

By using these standardized Level of Development, all design and construction professionals can proceed in an orderly sequence to provide the appropriate information, receive coordination feedback, and then move on accordingly to the next level.

Design Applications of BIM

With all of the foregoing in mind, let’s look closer at the options during the early design phase of a project when using BIM. In particular, consider the need to sketch options and visualize the form and mass of a particular concept. One of the misconceptions held by some practitioners is that BIM isn’t suited for this early work because a BIM model needs to be very detailed. The fact of the matter is that BIM models can be schematic too, with very simple sketch style drawings or line renderings being displayed quickly and easily. If desired, shaded solids and shadow lines can be shown without any additional detail, much the way a hand-drawing massing study might be done. Of particular usefulness, an initial shape can be identified and then stretched or adjusted in three dimensions to create simple or intricate forms, solids, and surfaces. Additional detail can be added as needed to the form in a conceptual manner, all of which can later be used as the basis for creating drawings at any level. The overall point is that the designer is in control of the BIM model, the information put into it, and the visual representations of it at whatever level is appropriate and expedient to the immediate need.

When the need arises for a conceptual drawing to be shown in the manner of an artistic rendering, BIM offers choices here too. Once again, there is a misperception that only very detailed, photo-realistic renderings can come from BIM software. The reality is that a full range of artistic styles can be selected and used for representing a design. This can include 3-D images that display as sketch lines, shaded or unshaded solids, variously colored images, or painting styles. It is also possible to switch quickly and easily between different styles, including monochromatic, sepia tone, colored, and others.

Of course, if a fully detailed, photo-realistic rendering is desired, that can be done using the BIM software as well. The model just needs to have the appropriate level of detail added for the area being shown (i.e., exterior facades or interior spaces, etc.), and a fully developed rendering can be produced. This level of rendering can be inserted in photographs or have a rendered setting included with other features such as people, cars, trees, etc. all added as desired. In some cases, it is even possible to use software to take the image of a model and incorporate it directly into a photograph to show the size, scale, and/or texture of the design in the context of its setting. That is a particularly appealing for urban design projects, renovations, or designs where the site and setting are a significant design consideration.

The point here is that the BIM model and software are the source for all types of conceptual drawings, whether 2-D plans, elevations, or sections or 3-D visualizations for exterior or interior spaces. There is no need to leave the BIM program and use another software program—everything can be done internally. Then, as further design decisions are made and the model is updated, the visualizations will also update. This allows for multiple quick studies to be prepared and compared with input from building owners, public entities, and other design and construction professionals.

High-Quality Construction Documents Generated from BIM

Once a design concept is finalized, then the design development and construction document process begins. The Level of Development Specification can be useful here as a means to determine what information and attributes need to be added to the building objects/Model Elements to move them from generic items to the specific parts and pieces of the building at hand. Essentially, this is a process of going into the model and updating the information associated with each aspect of the elements. That can include changing from generic items to specific products with exact size and performance data or verifying connection and support details for different elements. Additional information for specifications, cost estimating, or project scheduling can also be added to items to allow for a full database to be realized and used. In this way, the design model is updated and becomes a full building information model with all of the relevant information captured for construction.

Customized Control of Documents

With the model updated, the design team needs to recognize that it now has everything needed in the model to create high-quality, coordinated 2-D drawings. Some architects have occasionally thought that this represents some type of a compromise on the quality of the drawings. In fact, BIM offers more options, versatility, and control over the drawing output. Everything from page layout to coordinated notes (including keyed notes linked to standard wording) down to the line weight and thickness of different items and graphics on the page can be selected. Understanding the flexibility and customization of BIM software means that drawing protocols can be set up within the BIM program that match national standards, in-house office procedures, or client-mandated requirements. And those options can be changed any time to suit differing project requirements, new client needs, interdisciplinary coordination, or updated standards.

This customization of construction documents can be manifest in a number of different ways. Plans and elevations can all be generated directly from the geometric and dimensional information in the model and depicted at selected scales with any desired associated data displayed (i.e., labels, materials, etc.). Sections can be cut virtually anywhere and in multiple locations as needed. From a graphics standpoint, the legibility and clarity of the drawings can be controlled by assignment of drawing conventions to any of the BIM objects or drawing outputs.

Another time-saving and useful feature of most BIM programs is the ability to automatically generate schedules for doors, windows, partitions, finishes, etc. directly from data information contained in the model. Since all of the appropriate information or data is contained in the fully developed elements, it does not need to be input separately again. Instead, the designer selects which information to show and the software will populate the rows and columns of the schedules accordingly. In most cases, if something changes in the design, then the schedule will automatically update, thus serving as its own coordination check.

Document Coordination

Coordination between disciplines is a critical step for every project and is often cited as the number-one source of client complaints and claims. This is an area where BIM can be exceptionally helpful. While many consulting engineers may have their own specialty software that they prefer to use for design and calculations, they should also be able to produce outputs that can be entered directly into the main model in a fully integrated manner. In this way, the compatibility of systems and the space coordination of everything in the building can be reviewed, assessed, and adjusted as needed. That means structural information can be shown and coordinated with architectural information. Mechanical, electrical, and plumbing equipment, lines, and fixtures can be located and coordinated for clearances, access, or other design issues.

A big opportunity for improved coordination is found in the capability of the three-dimensional model to provide “clash detection” of different building objects/elements. This is a feature where the computer model alerts the designers if something like a beam, pipe, duct, or any other object is passing through the same space as another object, such as a different architectural, structural, or MEP element. Reviewing, assessing, and resolving these conditions in the computer model compared to doing so during construction is dramatically easier, takes less time, and is less costly to all involved.

Additional Documents

Another time-saving feature of using a central BIM software program for projects is that data can be used to generate additional, supplemental documents or deliverables separate from the construction drawings. These could include things such as cost estimates, energy models, and even project specifications. Since all of the information related to these things is already incorporated into the fully developed model, it is once again a matter of selecting the information desired and using the capability of the software to collect, display, and present it.

Overall, the key to better construction documents with BIM is to allow the people to do what they do best (i.e., design, assess, review, synthesize, resolve, etc.) and rely on the computer to do what it does best (i.e., store information, do calculations, present data, identify conflicts, etc.) In this way, quality construction documents can be customized to suit the needs of a firm or project and promote the full and complete coordination between different building elements and design disciplines.

Conclusion

BIM has emerged as more than just a better way to design in three dimensions. It has been shown to be a central tool for all types of documentation related to the design and construction of buildings. By using the appropriate Level of Development guidelines, all phases of a project can be conceived, developed, visualized, documented, communicated, and coordinated between all involved. Recognizing the full potential of BIM not only means better drawings and better projects, but it also means that firms have the capability to operate more efficiently, with more creativity, and potentially with more profitability. Embracing this full potential has been demonstrated with numerous firms around the world, making it clear that those who aren’t on board may get left behind.

End Notes

¹The full 2016 LOD Specification can be downloaded for free at bimforum.org/lod.

²UniFormat Numbers and Titles used in the LOD Specification are from UniFormat, published by CSI and Construction Specifications Canada (CSC), and are used with permission from CSI. For a more in-depth explanation of UniFormat and its use in the construction industry, contact 800-689-2900 or visit www.csinet.org.

Peter J. Arsenault, FAIA, NCARB, LEED AP, is a nationally known architect, consultant, continuing education presenter, and prolific author advancing building performance through better design. www.pjaarch.com, www.linkedin.com/in/pjaarch