- Watch out
- What it costs
- Experienced readers
- Remember
- In BIMpedia
On most projects the drawings are still the contract documents, and the model is issued alongside them. Both are read by people who will build from them. When they disagree, nobody on site stops to ask which one is right: they build from the one they opened.
Late in technical design, the architect moves a riser wall 150 mm on the plan with drawing lines, to meet a deadline. The model isn't touched. The duct contractor fabricates to the model; the drylining contractor builds to the drawing. The ducts don't fit the riser.
The same change is made in the model; the plan updates itself. Drawings and model are issued together as revision P04, from the same saved version. The duct contractor, the drylining contractor and the clash test all see the same riser.
One source, two views
| Belongs in the model | Fine as 2D on the drawing |
|---|---|
| Positions and sizes others set out or measure | Large-scale construction details (1:5, 1:2) |
| Data others check or schedule (fire rating, type) | Notes, dimensions, tags, keys |
| Anything clash-tested | Graphic emphasis, hatching |
Every issued document carries a revision (P01, P02, C01...) and a status (what it may be used for, such as for coordination or for construction). Drawings and the model they come from should carry the same ones, so nobody can mix versions.
At revision P03 you issue: the model (exported 12 March), floor plans (printed 10 March), a door schedule (exported from the model on 12 March) and a wall-types drawing with the partitions drawn in 2D. List what could disagree, and what you'd change for P04.
Key takeaways
- Drawings are generated views of the model plus annotation; the model is the source.
- When drawings and model disagree, contractors build from whichever they open first.
- Issue drawings and model together, with the same revision and status.
- 2D-only detail (lines drawn over views) is fine for details, never for things others take from the model.
Your notes
Related tool
Keep the drawing list with revisions and status, check numbers, and issue transmittals.
Open Drawing Register and Transmittals →