openBIM · clash matrices

Rimacos

Rules, not cells.

Python
IfcOpenShell / IfcClash
IDS 1.0
BCF
Navisworks XML
openpyxl
pytest

In plain words

A clash matrix is a big table that says which parts of a building should be checked against which, for example pipes against beams. On large projects it has thousands of cells that someone fills in by hand. Rimacos replaces the table with a few rules and produces the checks, reports and files that several programs need, including open formats any software can read.

The problem

A clash matrix grows with the square of the number of element groups. Filling in thousands of cells by hand, and turning them into thousands of separate clash tests, does not scale.

What it does

Rimacos (Rule-based Interference Matrices And Clash tests on Open Standards) turns a short list of rules into a complete clash matrix and the files to run it: search sets and clash tests for Navisworks, clash sets for the open-source IfcClash tool with results in BCF, an IDS file that checks the models contain the information the groups depend on, and an Excel matrix and HTML report for the project's BIM execution plan.

A rule says how two sets of elements are tested against each other. Each side can be everything, a discipline, a tag or a single group, and the most specific rule wins. A local browser editor handles the matrix, the groups and the rules.

Groups select elements by IFC class and type, by property filters and by classification codes, and models are found by their ISO 19650 file names, so the whole matrix also runs on open, free tools.

Features

Clash rules instead of matrix cells: a rule says how two sets of elements are tested, and the most specific rule wins
Each side of a rule can be everything, a discipline, a tag or a single clash group
Test types: hard clash, conservative hard clash, clearance, duplicate and none, each with a tolerance and a severity
Group priorities decide which side is responsible for fixing each clash
Navisworks output: search sets and Clash Detective tests as XML files, ready to import
Open-source output: IfcClash sets that run on IFC models and report results as BCF
An IDS 1.0 file (buildingSMART) that checks the models contain the classes, codes and properties the groups rely on
An Excel matrix for the BIM execution plan, which can be edited and imported again
HTML report and CSV list of tests, optionally with clash counts per test and discipline pair
Groups select by IFC class and type, property filters, classification codes and Revit categories
Models are found by their ISO 19650 file names
Local browser editor for the matrix, groups, rules and tests; imports classic matrix workbooks
Tests can be merged or kept one per pair of groups

HighlightA classic 133-group matrix had 8,778 cells. Rimacos reproduces every one of them with 4 rules, and the merged output needs 79 clash tests instead of 8,778.

Terms on this page

BIM: Building Information Modelling: designing a building as a shared 3D model that also holds data about every part, instead of separate drawings.
Revit: Autodesk's main software for designing buildings as BIM models. Most architects and engineers use it.
Navisworks: Autodesk software that combines the models of all disciplines into one and checks them for clashes.
Clash: A place where two parts of a building model collide, for example a pipe running through a beam.
IFC: An open file format for building models that any BIM software can read. It is maintained by buildingSMART.
BCF: An open format for passing model issues, such as clashes, between different BIM programs.
IDS: An open format that lists the information a model must contain, so that it can be checked automatically.
ISO 19650: The international standard for managing information on BIM projects, including how files are named.

See it

Screenshots & demos