Clash detection is the single most valuable BIM coordination activity. Done well, it prevents costly on-site rework. Done poorly, it generates mountains of irrelevant data that teams ignore. Here's how to do it well.
Start with a clash detection strategy. Define which discipline combinations to check (structural vs. MEP, architectural vs. structural, etc.), what types of clashes to report (hard clashes, soft clashes, clearance violations), and what tolerance thresholds to use.
Model quality comes first. Running clash detection on poorly modeled BIM is a waste of time. Establish model quality standards: correct element classification, proper level-of-detail, accurate spatial coordinates, and consistent units.
Use clash detection matrices. Not every discipline needs to be checked against every other discipline. A well-designed matrix identifies the 15-20 most critical intersection checks out of potentially 100+ combinations.
Filter aggressively. Out-of-the-box clash detection generates thousands of results. Use spatial filters (check only specific zones or floors), element filters (exclude minor elements like hangers and brackets in initial passes), and tolerance filters (ignore clashes under 10mm for initial review).
Group and cluster related clashes. A single misaligned duct may trigger 50 individual clashes with surrounding elements. Grouping these into a single issue reduces noise and focuses team attention on the root cause.
Assign clear ownership. Each clash must have a single responsible party. Use a RACI matrix to define who Resolves, who Approves, who Consults, and who is Informed for each discipline combination.
Establish a review cadence. Weekly clash detection reviews work well for active construction projects. Bi-weekly is sufficient during design phases. The key is consistency — missed reviews compound into larger problems.
Track metrics over time. Monitor the total number of open clashes, resolution rate, average time-to-resolution, and recurring clash types. These metrics reveal systemic coordination issues and measure team performance.