Building a structure
A BOM is a parent part with child parts and quantities, and children can themselves be assemblies with their own children. The structure is the product. Adding a part to an assembly changes every product that assembly appears in — which is why where-used matters before you edit.
NW-1200 · Control unit
3 levels · 84 lines · baseline 2026-03-01
Compare
Comparing two structures — two variants, or the same product before and after a set of edits — produces the list of what differs. It is how you answer "what actually changed", which in the absence of change control is the closest the module gets to a change record.
| Compare | Answers |
|---|---|
| Two variants | What is different about the export model. |
| A structure against its baseline | What has drifted since the last snapshot. |
| Two baselines | What changed between two points in time. |
Baselines
A baseline is a snapshot of a structure at a moment — what the product was when you shipped a batch, quoted a price, or sent a design out for manufacture. Without change control, baselines are the mechanism that makes a structure historically answerable at all, so take them at the points that matter.
Taking a baseline records a state. It does not gate anything, require a sign-off, or prevent further edits. If your process needs an approval before a design is released, that process lives outside this module today — see Changes.
- Baseline before sending anything to a manufacturer.
- Baseline when quoting, so a price can be tied to a specification.
- Baseline at the end of a development phase, even if nothing formal happens.
- Name baselines so a person can tell them apart. Dates alone stop being useful at about six.
What this does not do
A structure is current. There is no date-effective or serial-effective BOM.
Parts carry no cost, so a structure totals none.
One structure — the engineering view. There is no separate mBOM with process steps.
Anyone with the module can edit a released structure.
There is no standard interface out to a planning system.
Questions
How many levels are supported?
Enough for real products. Depth is not the constraint; discipline is.
Can a part appear twice in one assembly?
Yes, as separate lines — different reference designators, for instance.
Can we roll back to a baseline?
You can compare against one. There is no restore.