Helping 2D Subcontractors in a 3D World
I have worked on many projects for design and construction firms creating and providing training on BIM processes. Throughout this time I have noticed, as I’m sure most of us have, some apprehension to implement and utilize this type of technology. Although BIM has shown great returns for many projects, the implementation has been slow in developing. This slow development has contributed to companies of all sizes putting BIM on the back burner in anticipation of a sure thing or at least knowing that they have been successful in doing what they have always done.
BIM can create some headaches and isn’t always easy to incorporate, especially in areas of the U.S. that haven’t quite adopted this technology. The reason for this is simple—some areas of the country don’t have the manpower or money to invest in learning and customizing BIM. If the complete team isn’t utilizing BIM on a given project, that project can come to a crashing halt when all of the elements aren’t modeled or well-coordinated. All it takes is one discipline that isn’t modeled or coordinated and the project might as well be in 2D. Although this can happen in design firms, it is especially exaggerated in subcontracting firms. The following information has been written for subcontractors, but can be used for general contractors and design firms as well.
When an owner requires BIM on a project, it can produce a varying number of problems for a company that hasn’t instituted BIM. One of the main reasons I started AEC BIM Services is because I saw a need for this exact instance. Sometimes, when BIM is being used on a project, it’s easy to get caught up in the 3D aspect and assume every element is coordinated because it has been modeled. There can be a disconnect between the modeler and the project manager/foreman because each other’s job descriptions don’t always cross paths. We sometimes put aside everything we have learned from our 2D processes throughout time and rely on 3D processes in which all may or may not fit our personnel or company. I have noticed many subcontractors that were completely lost in the 3D world. It wasn’t their fault. They never had to worry about producing from this technology and they have always been able to build without it. What is hard to realize, before BIM implementation, is the typical LEAN approach. You don’t realize there is a problem until you look for it. The data, coordination, and collaboration are enough to save many hours and produce a better, more sustainable outcome.
In a typical project using BIM, the owner requires BIM because of the benefits imagined. The GC isn’t usually chosen because of their knowledge of 3D technologies. Even if the GC is well-versed in BIM, they really only provide coordination efforts to the team. It is left up to the subcontractor to complete their models and, most of the time, their own coordination. This can be an impossible task especially since the typical subcontracting firm doesn’t have the personnel required to model and coordinate in 3D. So, what does the subcontractor do? They could start looking at anyone on the project team that can produce 3D and try to hire them for modeling and coordination purposes. This isn’t the ideal situation because the other team members are trained in producing their specific discipline and are already too busy as it is. Granted, it can work, but it is not ideal.
Hiring an outside firm is a viable option. Third-party BIM firms have a good number of resources and usually have personnel that are trained in all disciplines. It’s hard to know what to expect, especially if it is the first time hiring a BIM firm.
Steps for a Typical Project
The BIM firm will meet with the project manager and/or the foreman for that project and explain the options the subcontractor has. This can range from 3D modeling and coordination services to Total Station layout to prefabrication modeling. I use a form that has all of the appropriate options listed on it, which I complete while sitting with the subcontractor (see Figure 1).
Figure 1: BIM checklist
- After all of the options are selected, a quote will be issued for services. This quote will contain project understanding, schedule for completion, and a cost of services breakdown. At AEC BIM Services we issue a lump sum quote based off of some information for the project. So the first number quoted is the last number quoted. Most firms, however, issue an hourly rate.
- After the quote is accepted, the BIM firm will then grab any bit of information they can from sketches to CAD files for use while modeling the building system. Most often the BIM firm will sit down with the subcontractor to go over their specific building standards as these will need to be incorporated in the model. If there has been a design model created for this discipline, it will also be used as a guide.
- The BIM firm will then take the information given and create a model while working with the subcontractor to assure buildability and coordination with the other disciplines.
- The BIM firm will participate in all of the appropriate coordination meetings and conference calls with the project team throughout completion of the building system. It is the intent of the BIM firm to act in the best interest of the subcontractor.
- When the coordination is complete, shop drawings will be created with dimensional and elevation information (see Figures 2 and 3). These shop drawings are accurate and can be used in the field during construction.
Figure 2: Mechanical dimensional sheet
Figure 3: Mechanical elevation sheet
After construction, an As-Built model will be used as the deliverable as well as the drawings that were produced (see Figure 4).
Figure 4: Coordinated As-Built example
It is imperative throughout this whole process that the BIM firm explains to the subcontractor exactly what is happening at every stage of construction and the lines of communication are open.
After completion of the initial project it will be time for the subcontractor to start making a plan for future BIM projects. One of the first items to consider is the extent the subcontractor can go to produce BIM in the future. Is it cost effective, are there available personnel in the area, will there be enough projects to sustain a BIM department are some of the questions that need to be asked. If it isn’t beneficial to start a BIM department, a third-party BIM company should suffice. However, if the need persists and a BIM department is in the subcontractors’ future, here are a few items to consider:
A meeting with the IT department will help further the understanding of what needs to be purchased such as hardware, software, and additional network space.
Templates need to be created. Templates must contain company standard information such as Annotation Symbols, specific company building elements, and company Titleblocks. The template also needs to be configured to match company standards. Settings such as lineweights, linetpyes, system information, and annotations are just a few.
An in-house company BIM standards manual is needed for continuity in modeling and processes. This manual will lay out which families to use in certain instances. In 3D, more so than 2D, it is essential for all BIM personnel to be on the same page because of the ramifications of poor coordination.
It is always a good idea to create a BIM Project Execution Plan, at least for in-house use. This plan will help to identify project demands, possible BIM issues to consider, and ownership of elements and processes. There are a lot of good examples of execution plans online, namely the Penn State University and Indiana University examples.
A training program needs to be set up. In a typical BIM department there will be a BIM Manager who has the responsibility to complete high-level tasks and train less-experienced employees. I have always found that training during a project is way more efficient than training from a book using example models. Training on a real project allows the inexperienced user real-world experience and, at the same time, a project is being completed. This cuts down significantly on overhead costs.
A third-party BIM services firm can help with all of the above items. The main issue with transitioning to Revit is that it takes expert-level experience to create families and customize templates and standards. This family creation and customization needs to be done in the beginning of BIM transition. Therefore, either an expert level user has to be hired in the beginning or a third-party firm can handle this while training entry-level personnel at the same time (see Figure 5).
Figure 5: Custom family example
Transitioning to Revit will be a daunting task, but one that will help to save time, money, and create more efficient projects. One thing to note: if any company elects to create a BIM department, it is important that there be substantial buy-in from upper level management. There are an abundance of firms that elect to start a BIM department without this buy-in, and they eventually go back to pre-BIM standards.