Why do generated elevator cab BOMs go wrong?
The first failure is unwritten knowledge. If one estimator remembers that a ceiling choice requires different framing, or one shop lead knows when an extra bracket is needed, the configuration model is incomplete. Rules encoded in one person’s head cannot be tested, revised, or applied consistently.
The second failure is a silent dependency. One option changes another option, a dimension, hardware set, labour operation, or purchased quantity without showing the user. The visible selection remains plausible while the BOM follows an undocumented branch. Dependencies should be explicit, versioned, and tested in both permitted and prohibited combinations.
The third failure is confusing a finish name with a purchasable material. A colour or visual swatch does not specify supplier, product, grade, thickness, sheet size, grain, coating, minimum buy, approved sample, or current availability. A finish that cannot be ordered should not resolve as an ordinary standard line.
The final failure is validating software logic without validating shop practice. A mathematically consistent list can omit reusable fixtures, backing, fasteners, edge treatment, bought-out assemblies, packaging, or a fabrication operation. Walk a real released job from estimate through drawings, purchasing evidence, fabrication, and revision history. The CAD-to-operations workflow for elevator manufacturing explains why geometry alone is not a purchasing instruction.