| 3D model | STEP, STP, IGS, IGES, STL, X_T | The geometry that will be cut, and the CAM program built from it | Free-form parts cannot be quoted accurately from views alone |
| 2D drawing | DWG, DXF, PDF | Tolerances, surface callouts, threads and datums, none of which a solid model carries | We quote to general tolerance and ask before assuming anything functional |
| Material and finish | Written specification | Cutting data, stock availability, and whether finishing is a separate operation | Quoted as an allowance, which is less accurate than naming the grade |
| Quantity and required date | Written | Whether the part runs one-up or on a dedicated fixture, and how it is scheduled | Quoted one-off, which is rarely the cheapest way to buy five hundred |
| Marked functional dimensions | Note on the drawing | Which fits are inspected and reported | Everything is treated as nominal, which adds inspection time without adding value |