BIM Clash Detection – Key to Conflict-Free Construction

What Is BIM Clash Detection?

BIM clash detection is a process that identifies conflicts among multiple construction models in a virtual environment. These conflicts, referred to as "clashes," occur when various design components, such as structural elements, HVAC systems, or electrical conduits, intersect or interfere with one another's buffer zones.

Architects, MEP (mechanical, electrical and plumbing) engineers, and structural engineers typically create their models independently during the design process. Consequently, when these separate models are combined into a single project model, there is a possibility that the individual components may inadvertently overlap or interfere with each other.

BIM clash detection identifies these clashes early in the preconstruction or design phase, which can help mitigate costly adjustments and delays during the construction phase. This process determines where design elements may overlap and identifies constructability issues, allowing teams to address them before proceeding to the next stage.

Best Tools for BIM Clash Detection

Autodesk Navisworks

Autodesk Navisworks is a widely used tool for MEP clash detection and coordination, enabling users to integrate various 3D models from different sources and identify conflicts.

Autodesk Revit

Revit functions as a BIM authoring tool that includes a built-in clash detection feature to identify clashes within the same or linked building models.

Autodesk Construction Cloud

Autodesk Construction Cloud offers automatic clash detection for models across different disciplines and formats when uploaded to Model Coordination.

Autodesk BIM 360

BIM 360 is an efficient tool for automated clash detection and rectification, also providing resources for preventing clashes.

Graphisoft ArchiCAD

ArchiCAD features a user-friendly interface and service panel, incorporating advanced conflict detection, client presentations, and rendering capabilities.

Solibri Model Checker

Solibri Model Checker is a tool that allows users to run rules and identify hard or soft clashes in BIM models.

BIMcollab

BIMcollab utilizes BIM to analyze digital models and detect workflow clashes and functional conflicts among various construction disciplines, systems, and components.

Common Types of Clashes in BIM

Hard Clash

A hard clash occurs when two systems or components occupy the same space or intersect. For example, a structural beam may be positioned where an HVAC duct is intended to be, or a plumbing pipe may be designed to run through an electrical conduit. These physical conflicts in design, if not addressed before construction, can lead to significant rework. Hard clashes are identifiable and can be costly if missed.

Soft Clash

A soft clash, sometimes referred to as a clearance clash, happens when a building element or component does not have sufficient space or buffer for effective and safe operation. This can involve maintenance access, safety clearances, or operational spaces. An example would be an AC unit lacking enough buffer space for servicing, which could hinder routine maintenance and lead to downtime, thus affecting the building's comfort and efficiency. Additionally, safety concerns may arise if a high-voltage wire is situated too close to a plumbing line, potentially resulting in electrical shorts or risks of electrocution if leakage occurs. Although soft clashes don't involve physical overlaps, they can still pose significant challenges related to safety, functionality, and maintainability. Identifying these issues early with the appropriate BIM clash detection tools can facilitate resolution prior to construction.

Workflow Clash

A workflow clash, also known as a 4D clash, involves scheduling conflicts or misalignment in project management. For instance, if the installation of electrical conduits coincides with the pouring of a concrete slab in the same area, this can lead to work stoppage, rework, and delays. Additionally, delivery of large pieces of equipment before an area is prepared for installation might create space constraints or risk damage to the equipment. Workflow clashes can negatively impact job site productivity if not identified in a timely manner. Effective identification and management of these clashes through BIM enhance scheduling and sequencing.

Best Practices for Effective Clash Resolution in BIM

• Early Detection: Implement automated clash detection tools to identify issues in the design phase. This approach facilitates the resolution of conflicts prior to the commencement of construction.
• Collaboration: Engage all relevant stakeholders—such as architects, engineers, and contractors—in the clash resolution process to promote informed decision-making.
• Categorize Clashes: Prioritize clashes according to severity (e.g., high, medium, low) to address the most critical issues initially.
• Clear Resolution Protocols: Establish a standardized workflow for resolving clashes, including the assignment of responsibilities and the tracking of progress throughout the resolution process.
• Visualization Tools: Utilize 3D models, virtual reality (VR), and augmented reality (AR) to improve understanding and facilitate clash resolution.
• Iterative Process: Conduct multiple rounds of clash detection as the design evolves to identify and address any new conflicts promptly.
• Optimize Design Solutions: Collaborate with team members to develop efficient solutions, which may include design adjustments or the use of prefabricated components.
• Integrate with Scheduling (4D BIM): Apply 4D BIM to identify and resolve clashes related to construction timing and sequencing.
• Encourage Flexibility: Maintain open communication among stakeholders and be prepared to adapt solutions based on changes in project scope or design.
• Post-Resolution Review: Validate solutions with relevant stakeholders and perform a final clash detection check prior to the start of construction.

Summary

BIM Clash Detection is the process of identifying and resolving conflicts between different building systems (e.g., structural, mechanical, electrical) within a 3D model before construction begins. Using specialized software, potential clashes—such as objects occupying the same space or being too close—are automatically detected. Early detection of these issues helps avoid costly delays, rework, and safety hazards during construction. Key benefits include improved coordination, cost savings, and higher project quality, although challenges like false positives, false negatives, and interoperability issues exist. Overall, BIM clash detection is essential for ensuring smooth and efficient project execution.