BIM clash detection unveiled: A step-by-step approach

Discover the best practices for executing BIM clash detection in construction projects and the positive impact of incorporating structured model reviews.

In the previous article of this series, we discussed the basics of clash detection: why it is elemental to the success of a project, what are various types of clashes, how to speed up checking, and how it ties into the whole BIM quality management.

Next, we go deeper into the model-checking process and discuss the business case for clash detection. 

The prerequisites for efficient BIM collaboration

A necessary starting point for successful model checking is a BIM Execution Plan. It explains the practices, requirements, roles, and responsibilities in the model-based process. One of the things to agree on is the BIM formats you use for model collaboration. As an open standard, IFC is the ideal choice.

From the clash detection perspective, a critical role is that of the BIM Manager or BIM Coordinator. They are responsible, among others, for the interdisciplinary BIM process and coordinating clash detection.

To make sure the clash detection workflow is smooth, a project should implement a CDE, Common Data Environment, at the project’s outset. It allows auditable communication and controlled sharing of the project’s digital assets.

You also need a capable and trustworthy tool for model checking and clash detection. Many BIM coordinators use Solibri Office for the task.

How to run clash detection

The process of clash detection is a standard routine in BIM-powered projects. It should start early in the project and continue until the positions or dimensions of the building components are fixed in the models. This implies that changes during the construction phase should be included in the models and checked before procurement and production.

Accesible stair rule
Example of clash detection in Solibri Office

1 - Import and aggregate models

Once the designers have checked their models internally for potential clashes, they submit IFC files for BIM coordination. The coordinator uses Solibri to aggregate the models into a single model for comprehensive clash detection across disciplines.

2 – Do rule-based checking

With Solibri Office, designers and coordinators can define specific clash rules tailored to the project's needs or universally applicable. These rules can range from simple geometric clashes to more complex functional clashes, like ensuring adequate clearance for installation and maintenance around equipment. Multiple versions of the same object can also be detected automatically.

With the rules set, Solibri scans through the BIM model to identify clashes. It ranks them according to their severity. For example, a small pipe penetrating a bearing wall is less critical than an extensive ventilation channel crossing a massive beam in the model. Some clashes are intentional and have been agreed upon between designers.

3 – Communicate and resolve the issues

BIM coordinators categorize and sort the clashes based on severity, discipline, or location. If necessary, they create an issue in Solibri Office and assign it to the person responsible. A coordinator can also provide a detailed report of the clashes.

In addition to virtual communication via the CDE, BIM coordinators typically arrange weekly meetings to present and discuss the clashes and other design-related topics.

BIM coordinators and designers can track the status of issues within Solibri Office. The software also allows automated comparison of changes between model versions, which is critical in the fast-paced design and construction process.

What is the business case for automated clash detection?

If clash detection with BIM is manageable with proper processes and tools, what is the payback for the investment?

A research paper, Cost-benefit analysis of BIM-enabled design clash detection & resolution (Chahrour et al., 2020), tried to quantify the benefits of BIM clash detection in substantial infrastructure projects. The estimated savings using the developed clash detection and resolution schema were 20% of the contract value. For example, the cost implications of a medium-category clash in the project were estimated at $1.6 million, whereas the corresponding BIM clash detection cost was $5,800.

Another case study by Simon Graham, Director at Opencore, compared the cost of manual design coordination versus automated BIM clash detection. The task was to review and approve the size and position of the builder’s work openings and the coordination of building services passing through them. The study concluded that for this single specific design coordination exercise, costs were reduced by 62.4%.

Several other studies on the subject arrive at the same conclusion: Automated clash detection has an exceptional ROI. It saves the design teams’ time, gives designers more time to resolve the issues, and reduces the number of field conflicts that lead to costly rework.

Extract More Value From BIM Data
Watch how to extract more value from BIM data, presented by Simon Graham from Opencore

Interested in learning more about BIM Strategies for cost-effective construction? Check out our webinar with Simon Graham on ‘Exploring innovative BIM strategies for streamlined design and cost-effective construction’.

The way forward

Clash detection is a necessary component of the BIM-powered construction process. Nevertheless, it is just a single aspect of the broader scope of data-driven design analysis and construction management. That is why professionals need a full spectrum of intelligent BIM management capabilities that Solibri offers.

Finding the middle ground
How to improve MEP coordination with Joe Magas, CEO of Fusiontek

The purpose of construction technology is to empower us and make our work joyful. As Joe Magas, CEO of Fusiontek, concluded at a Solibri webinar: “Coordination issues take away our happiness from the project from the people; it is distracting and troublesome. We want to eliminate that as much as possible.”