By Robert W. Elliot III, AIA NCARB
Leveraging new and current technology to improve our design methodology is at the core of what we strive for here at FreemanWhite. One tool we use is Navisworks, to improve design team coordination and thereby our deliverable documents and building information modeling (BIM).
Navisworks is a 3D design review software we leverage as a design coordination tool. It is a non-authoring software, meaning you can only look at—not manipulate—the BIM models. The key feature that we have integrated into our design methodology is its ability to find model clashes. There are three kinds of clashes: soft, hard, and workflow clashes.
- A soft clash is when a required clearance is violated.
- A hard clash, which is what we are looking for primarily, is when two modeled elements touch.
- A workflow clash is used by the construction sector to review workflow and installation processes.
Navisworks creates an itemized list of all clashes for review. Typically, this list is lengthy; it is up to the reviewer to filter out any false clashes and identify true hard clashes. Navisworks will review all models and files associated with the project at once for a complete review. We have found value in this process by identifying coordination items to improve our design and project constructability.
During the construction phase, this process is commonly referred to as clash detection. With the typical delivery process of Design-Bid-Build, the design BIM model is given to the contractor, who then uses it as a guide for their subcontractors to build a more detailed construction BIM model. What we are doing is similar, yet we have different goals. Our goal is to ensure constructability of the design intent, increase communication and coordination between the design team and the bidding contractors and/or the contractor for construction while ensuring a more effective design. This process is commonly called clash prevention.
As part of our design methodology, all of our projects receive clash prevention tests. One recent project using this process is a new seven-story, 225,000 square feet, 177-bed NICU tower. The report generated 55 true hard clashes that required time and thought to resolve. Reoccurring meetings were set up to gather the design team to work through each issue and track progress. The true clashes will be resolved before the final documents are released.
Integrating clash prevention into our design process will save time in the construction phase by allowing the construction BIM model to be built more quickly, thereby saving time and reducing RFIs from the field. While no model can be clash-free, we endeavor to be fully coordinated to ensure the quality of the BIM model. That quality has a big impact on vetting the constructability of a project. By leveraging this software, we use clash prevention reviews during set intervals of the design process to ensure that our design intent is fully coordinated and constructible, thereby limiting downstream delays.