The Process of BIM from Design to Construction
In a 3D world, BIM is the glue that holds design and construction together. In my experience, there are a lot of firms out there that aren’t sure what goes into a successful BIM project. In this article, I will sort through the steps that a firm normally takes to go from design through construction using BIM.
The process of using BIM models for collaborative purposes, leading up to and through construction, is a lengthy one. It involves a real investment on software and employees. In the firm I work for, The Austin Company(www.theaustin.com), we utilize Revit Architecture, MEP, and Structural, as well as Navisworks, 3D Studio Max, and AutoCAD.
In predesign, it is determined if BIM is going to be used on the project. Assuming that BIM is the approved method, the Architect gets started on the schematic model, either by using masses or real elements in a BIM environment. Once the schematic architectural model is prepared, a presentation will be given to the owner. A walkthrough or renderings is a necessity for this presentation. 3D Studio Max, in conjunction with Revit, helps in this task. The owner will then offer thoughts on the design, tweaks will be made, and the model is ready to enter into the design phase.
During schematic design, scheduling(4D) and estimating(5D) really start to get involved. Scheduling must make sure that this building can be built in the time allotted and estimating needs to make sure that they constantly track the cost of the project. How can BIM help with this? The BIM models need to be set up correctly from the start. For scheduling, the model has to be built with building in mind. The firm I work for is a design-build firm. We have begun to use Navisworks in the field. So, there are some modeling practices that we use that an A&E firm would not. We build our model for the schedule. For instance, our floors are modeled by the sequence of how they will be poured. We need to do this so the Navisworks schedule can be built correctly. For estimating, Project Parameters need to be added to the models.
This is important for two reasons. The schedules need be filtered correctly so estimating can utilize the model to help in their estimates. Also, the elements in the project need to have enough information so that estimating knows what type, size, etc… of element they are estimating. This is especially important in projects that are heavy on the process side. It is very laborious for estimating to try and count all of the elements of a process project from a 2D plan. BIM has enabled the design and construction process to be a totally collaborative effort. Typically, this is why a design-build firm can take less time from schematic design through construction of a project than an A&E firm that doesn’t have estimators or CM’s on staff.
During detailed design, collaboration is key. It is imperative that weekly coordination meetings take place in order to ensure that everyone is on the same page. In these meetings, the architects and engineers, project manager, estimator, scheduler and Construction Manager are in attendance. In this phase of the design process, Interference Checks and Coordination Reviews are done weekly. This is an obvious step to take, but a lot of firms don’t utilize the collaborative tools that BIM provides. Firms usually don’t think they have enough time to run Interference Checks or Clash Detections. What they don’t realize is that they will spend a lot more time and money fixing the mistakes in the field that could have been caught early in the design phase if they just would have spent the time.
Throughout design, there are certain modeling practices that need to be followed. For one, if you’re going to the trouble of modeling the project, it is more efficient to have the model used for more than just plan work. Scheduling, sections, elevations, and walkthroughs are just some of the coordinated processes that can make your BIM model more efficient and, if done correctly, can save time and money. Another important factor is ownership of elements. When we talk about ownership, we are referring to which discipline originally modeled an element. The owner is also referred to as the Model Element Author (MEA). When it comes to copy/monitor, the disciplines that copy/monitor an element from a linked model may have input into that element, but are not the owners of that element. Therefore, the owner of an element needs to pay extra attention to the coordination of that element. One of the best uses of BIM’s efficiency is one in which every element type is modeled only once. If there are multiple instances of the same element stretched across disciplines, this can be a headache for coordination and collaboration between models.
After the design is completed, construction is ready to begin. As discussed, throughout design, estimating and scheduling were updating their respective processes. This means that long-lead items have been purchased and the schedule has been modified to ensure project completion by the due date. Also, site work has already been started and foundations are ready to be poured. During the construction phase, Navisworks will be available in the field and the design models may have been replaced by models from the subcontractors. The Construction Manager and field superintendent will work with the design team to make sure that the design intent is followed, and they will run their own Clash Detections on all models. With Navisworks monitoring and workflow tools, identified problems can be reported and tracked through resolution. Construction can be simulated to make sure everything is being built on time. This process was made easier by the fact that BIM was used early in the design phase. We have found that there are significantly less RFI’s when BIM is used correctly in all phases of a project. Along with that, the owner has actually seen what he/she is getting with the aid of walkthroughs and accurate renderings.
BIM has created a solid connection between design and construction that had never been felt before. Instead of asking how we can get architects, engineers, and construction managers to collaborate efficiently, we are now asking how we can use BIM to make the process even faster and more efficient.
Matthew Hill is the BIM Manager for The Austin Company, a Design-Build AEC firm with offices in Cleveland, Irvine, Atlanta and Kalamazoo. He has been customizing, utilizing and providing training for AutoCAD for 16 years and Revit for 6 years. Matthew has produce Revit projects with multiple Architectural clients, all with varied experience levels. Matthew currently sits on the executive board for NEORUG. He was a speaker at Autodesk University in 2008 for "Efficient CAD Management Through Customization". He has also given multiple presentations on Revit and the multi-disciplinary functions of Revit as well as training sessions for Architectural clients.
LinkedIn Public Profile: http://www.linkedin.com/pub/matt-hill/1b/191/a88