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Keep Your Project on Track with Clash Detection

Russ Tamblyn, CM-BIM Principal, Director of VDC
Clash detection, a powerful 3D coordination technique, improves project outcomes by stimulating collaboration and reducing delays and rework. 

Imagine you are installing equipment on a project and you find a major issue that must be fixed. This could be a beam and a pipe trying to occupy the same space, a lack of clearance space around important equipment, or even a conflict between work crews and scheduling sequences. Designs must be reworked, schedule is impacted, and construc­tion is halted until designers and construc­tors can coordinate to fix the issue. Thousands of dollars and multiple days—or even weeks—later, the issue is fixed. But the impact to project cost and schedule is irre­versible.

Though project teams work hard to identify conflicts like these before construc­tion begins, the breadth of information project members must account for is substantial and vulnerable to human error. Clash detection is one of the many downstream uses of a robust 3D or BIM model and a valuable tool for identifying conflicts within the virtual design and construc­tion (VDC) process. Instead of comparing project designs on paper for compat­i­bil­ity, teams can now rely on 3D coor­di­na­tion, or clash detection, to more effectively identify and address potential conflicts to prevent issues.

Under­stand­ing the Benefits
Clash detection provides a unique perspective on the various disciplines that contribute to a working 3D project model. The process leverages numerous 3D models and data from varying disciplines, including archi­tec­tural, structural, civil, process, and electrical to identify and resolve clashes before design is complete or construc­tion begins. Using clash detection software, project members can easily review 3D model conflicts and generate clash reports comparing 3D models of individual project systems throughout the design, construc­tion and startup of a project to identify and address areas of conflict between disciplines. This helps maintain a high level of coor­di­na­tion between disciplines, stimulating important conver­sa­tions earlier so conflicts can be identified and addressed as early as possible.

3D Coor­di­na­tion in Action
Previously, project teams either identified clashes as they arose throughout construc­tion or compared 2D drawings on paper to their digitalized versions to identify discrep­an­cies. These methods were still vulnerable to human error, often creating costly delays and potentially halting the project schedule until the issue was resolved. With modern methods and tech­nolo­gies like 3D modeling, designers and construc­tors are no longer limited to comparing multiple 2D models. The BIM modeling process, combined with software capable of clash detection, such as Navisworks, brings 3D coor­di­na­tion like clash detection to life so designers and construc­tors can identify conflicts much easier and earlier than ever before.

Navisworks provides a collab­o­ra­tive platform to identify and inspect clash sets, cate­go­riz­ing them as:

  • Hard clashes: inter­sec­tions between materials where two or more elements from different disciplines occupy the same space. Navisworks can identify hard clashes through geometric means, pinpointing clashes like a beam running through a pipe.

  • Soft/Clearance clashes: potential clashes between components that lay within a particular distance of other components, identifying elements of inter­dis­ci­pli­nary models that come within close proximity from one another without actually colliding. Identifying these clashes helps pinpoint issues in areas that require working space for access, insulation, or safety.

  • Workflow clashes: occur when there is a scheduling issue between work crews and equipment fabrication, delivery and instal­la­tion in the project timeline.

These clas­si­fi­ca­tions help identify and track the different types of clashes that may occur between design disciplines or subcon­trac­tors prior to instal­la­tion, flagging inter­fer­ences as they are identified, reviewed, approved and/or resolved. Clash detection is not limited to the design phase—during construc­tion, clash detection continues to play an important role in virtually resolving clashes between all subcon­trac­tors, designers, owners and operators before substantial procurement investments are made and instal­la­tion of equipment has begun.

Bringing together the different facets of project planning helps create more accurate as-built drawings & visualize construction efforts before equipment hits the ground.
Russ Tamblyn, CDM Smith Director of VDC
Russell Tamblyn Russell Tamblyn
If a picture is worth a thousand words, a model is worth a million.
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The Added Value of Clash Detection
One of the most impactful aspects of clash detection is its ability to promote meaningful discussions among the project team on equipment placement, accessibility, maintenance and operations tasks and more. Using clash detection in a robust 3D or BIM model guides teams to have conversations earlier on in the design phase, focus on the right issues and address them quickly by level-setting expectations and providing the same version of the truth to all project members and stakeholders. When you bring together all the different facets of project planning, project members can create more accurate as-built drawings and visualize construction efforts before any equipment even hits the ground. The results are reductions in field conflicts and increased productivity.

With the power to identify, investigate and communicate potential conflicts, project teams can coordinate on a higher level to categorize and track interferences and even prioritize the issues that require immediate attention. The high level of collaboration and organization clash detection engenders reduces the risk of human error during model inspection and minimizes the amount of rework and change orders needed, ultimately minimizing potential impact to project cost, completion date and quality. 

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