12d Model Clash Detection

12d Model Clash Detection

12d Model Programmer Hanh Cao addressed our 2018 Technical Forum audience about Clash Detection in 12d Model.


12d Model 12 – Supported Data

  • Services
  • Pipelines
  • Water Nodes and Links
  • Trimeshes
  • TINs (v14)


BIM -> Check/clash -> Clash detection (then Detection or Rules)



Under ‘Clash Rule Sets’, each set of rules (with its individual rules following) is laid out. Services covered include Water, Electricity, and Gas.

For each individual rule, name and description can be set, as well as parameters such as For (Dynamic) and Against (Static) Data, Link/Pipe clearance, Node/Pit clearance, Trimesh clearance, and TIN above/below clearance.


The panel itself is quite simple – just a For and Against Data Source with no overlap, rules and output models, and report types to set.

Data Selection for Each Rule

  • Data is selected using Model -> Name (requires a good naming convention)
  • ‘For’ set is selected first
  • ‘Against’ set is selected second
  • Any overlap with the ‘For’ set is removed from the ‘Against’ set
  • Tolerances are applied to the ‘For’ set
  • The rule is to check ‘For’ vs ‘Against’

Clash Checks

Two kinds – Direct Clash or Tolerance Violation – i.e. creating a ‘buffer’ around objects using rules and then checking whether any other objects violate that tolerance.


Watch Hanh’s presentation (link coming soon)!