Chapter 4 recap
Files, names and coordinates
The key takeaways from this chapter’s 3 lessons.
Naming information containers
- Every file, model or drawing is an information container and needs a unique ID that follows the project convention.
- The ISO 19650 pattern combines fields: project, originator, volume or system, level or location, type, role and number.
- Each field uses short codes from an agreed list, so names can be checked automatically.
- Status and revision are metadata in the CDE, not part of the container name.
Shared coordinates and georeferencing
- Every model has an internal origin; teams must agree how their models relate to each other and to the site.
- Georeferencing links the model to a projected coordinate reference system, identified by an EPSG code.
- A rotation and a translation (and sometimes a scale) describe how model coordinates map to grid coordinates.
- Check the result with surveyed control points: small residuals mean the model is where it should be.
Checking an IFC file before you share it
- Check the header: schema version, exporting application and view definition.
- Check the spatial structure: project, site, building and the expected storeys, with elements assigned to them.
- Watch for proxies, unnamed elements and elements outside the spatial structure — they usually point to export mapping problems.
- Check that required properties are present and filled, ideally against an agreed list or IDS file.