In plain terms: Reconstruction is not tracing. It is working out what a set of
2D sheets actually establishes about a ship, building only that much geometry, and
recording everything the sheets leave unresolved as a named question instead of
filling it in.
The problem reconstruction solves
There are two established ways to get a 3D model of a ship, and neither works for most vessels in service.- Scan it. Laser scanning and LiDAR capture the ship as it is today, but only the surfaces a scanner can see. Structure behind a bulkhead, inside a tank, or under insulation does not appear. It also requires physical access to the vessel, which usually means it is already in dock, which is exactly when you needed the model.
- Use the design model. This assumes one exists, is complete, is editable, and still describes the ship after decades of repair. For an in-service vessel, at least one of those is almost always false.
What a drawing sheet actually establishes
The central discipline is separating what a sheet shows from what a reader might assume from it. Take a main hatch. A plan sheet may establish the hatch perimeter clearly. That same sheet says nothing about coaming plate thickness, cover layout, attachment detail, or present condition. A longitudinal profile sheet may establish the hatch’s envelope in profile without defining its transverse section. Both facts are real and useful. Neither is a complete description of the hatch. Forge records that distinction explicitly. Each sheet contributes what it establishes, scoped to what it establishes, and the reconstruction is built from the intersection of those contributions rather than from one reader’s overall impression of the drawing set.The pipeline
1
Admit the sources
Every drawing sheet, survey record, and report enters as a with its
version, its authority, and where it came from attached. Sources are locked
once admitted. They are never quietly edited to make a later result work.
2
Read each sheet for what it establishes
Each sheet is interpreted into scoped claims: this perimeter, this station
spacing, this profile envelope. Every claim stays attached to the sheet and
region it came from, which is applied to drawings.
3
Cross-reference the views
Plan, profile, and sectional views have to agree about the same physical thing.
Where they agree, the reconstruction is well supported. Where they conflict,
the conflict is recorded as a conflict. It is not averaged away, and neither
view is silently preferred.
4
Build only the geometry the evidence supports
Geometry is generated for what the sources establish. Where they do not
establish a shape, no shape is generated. The reconstruction is deliberately
bounded by its evidence rather than completed for appearance.
5
Name what is unresolved
Every unresolved region becomes a selectable identity carrying its evidence
envelope and the specific question that would close it: which drawing, survey,
measurement, or observation is needed. Gaps are inventory, not absence.
6
Check against type and class precedent
Reconstructed components are checked against the vessel’s own type and class
precedent. This is a consistency check that surfaces suspect results, not a
source of geometry. Precedent can flag that something looks wrong; it is never
used to invent what the drawings did not say.
7
Route to human review
A reconstruction is a proposal until an accountable person accepts it. Nothing
becomes approved engineering geometry on import.
Why gaps stay visible
A reconstruction with no visible holes demonstrates better and is worth much less. Once invented geometry is in a model file, it is indistinguishable from evidence-backed geometry. Someone will eventually plan a repair against it, order steel to it, or hand it to a surveyor. The failure surfaces at the worst possible moment, and by then nobody can tell which parts of the model were ever real. So an unresolved region in a Forge model does not disappear and does not get filled. It stays as a question with a boundary around it. That makes the model honest in both directions: it tells you what is supported, and it tells you precisely where it is not. It also makes collaboration concrete. A named gap is a specific research brief. A partner with a better drawing, a current survey, or direct observation can close one and see exactly what it changed.Time states stay separate
A ship’s record spans decades, and different records describe different moments: original construction, a later modification, one survey, a different scan years later. Forge does not merge these into a single confident model. Each remains a distinct, labeled evidence state. One configuration serves as the primary assembly, and the others stay available for comparison. Two records can both be accurate without describing the same side, surface, date, or physical reference. This is what makes it possible to ask a question that matters in repair work: what changed, and when.From reconstruction to reconciliation
Reconstruction produces a model of the ship as the record describes it. Reconciliation is the ongoing job of keeping that model true as inspection findings, repairs, and retrofits change the vessel. The same discipline carries across. A thickness measurement that disagrees with the model is recorded as a located conflict, not an overwrite. A completed repair updates the model through the same review gate as everything else.See it on a real vessel
A complete 1886 ship reconstructed from its historical drawing set, with all
of its open questions still visible and selectable.
How geometry becomes evidence
What separates a picture of a measurement from a traceable engineering claim.