A ship is built from its drawings.
Check every revision before it reaches steel.

1. What it reads Two revisions of one sheet, exactly as the drawing office issued them.

   A review would start from the revision under review and the revision before it, each exactly as issued. Each file is identified on arrival, and every later statement cites it. Before anything is compared, the review confirms that both files are the same drawing and sheet and that one follows the other. A failed check stops the review: two sheets that may not be the same drawing are never compared as if they were.

   A scan, a pasted detail or a stamp is reported as not comparable until a reader for it has been measured on labeled sheets.

2. What it reports Every change, with both values. Nothing unreadable reads as unchanged.

   Each element is reported as unchanged, changed (with both values), added, removed or not comparable. Not comparable is never folded into unchanged, because a region nobody can read is exactly where an unrecorded change would hide.

   Every change is then checked against what the revision says about itself. A change the revision records is a recorded change. A change it does not record goes to a person: finding 2 on the sheet above is that case.

3. What it checks Three classes of rule, each stating what it must never conclude.

   Comparison says what changed. Rules say what is wrong with the sheet as it stands, changed or not. Every rule is written down with the one conclusion it may reach, the conclusion it must never be read as reaching, and when it cannot be evaluated.

   1. Internal consistency Does the sheet agree with itself?

      • A parts-list quantity equals the count drawn (finding 1)
      • A fillet weld carries a size, or a note gives one (finding 4)

      Reads

      The sheet alone.

      Never concludes

      That the sheet is right. A sheet can agree with itself and still be wrong.

      Cannot be evaluated

      When a value it needs sits in a region it cannot read.

   2. Reference integrity Is everything the sheet cites at the revision that governs?

      • A cited drawing is at its current revision (finding 3)
      • A cited procedure or standard detail exists under the number cited

      Reads

      The yard’s drawing register, read at review time.

      Never concludes

      That the cited drawing is correct, or released for this work. Current in the register is not released for production.

      Cannot be evaluated

      Without the register. Then every reference is cannot establish, as finding 3 shows on a sheet read alone.

   3. Rules the yard adopts Does the sheet follow the drafting and design rules the yard has written down?

      • Every title block field the yard requires is filled
      • Plate thicknesses come from the yard’s stock list

      Reads

      Rules the yard writes, owns and versions, each naming the clause of its own document it encodes.

      Never concludes

      Conformance with any published standard or classification rule. A rule encodes the yard’s reading of its own document; whether that reading matches a class society’s rule is for the yard and the society to settle.

      Cannot be evaluated

      When the rule’s owner has not confirmed it for this drawing type.

4. Four statuses, and who decides each Why the fourth, cannot establish, has to exist.

   Every finding carries its rule, its place on both sheets, the values read and what it cannot establish. A finding a reviewer cannot check against the drawing is not raised.

   A checker with two answers has to turn every missing input into one of them. If it raises a fault, engineers learn to dismiss it; if it stays silent, silence reads as a pass. Either way the cost falls on the faults a sheet read alone cannot catch, and those are the ones that reach the floor.

   Cannot establish names the missing input and who holds it, so the gap is closed rather than guessed. It is the rule VeldBuild’s readiness already follows: unknown is a third answer, never a pass.

   1. Recorded change

      The revision records this change. Not a fault: it is the list of what a checker has to check.

      Decides

      The responsible engineer approves or rejects the revision; document control records the approval.

      Closes

      When the revision is approved or withdrawn. Recording a change is not approving it.

   2. Verified inconsistency

      The sheet contradicts itself between two things read directly from it: a count and a quantity, a dimension chain and its total.

      Decides

      The drawing checker accepts or rejects the finding. The responsible engineer, a different person, approves the correction.

      Closes

      When an issued revision makes the rule pass. A markup that passes is a proposal, not a closure.

   3. Potential issue

      Something a rule can see and cannot judge: a change nobody recorded, a departure from a general note. Whether it is an error depends on intent, which is not on the sheet.

      Decides

      The responsible engineer states the intent.

      Closes

      When the intent is recorded. If the departure stands, the drawing owner records it in a revision.

   4. Cannot establish

      The rule needs an input the review does not have: the drawing register, a welding procedure, a region it could not read.

      Decides

      Whoever holds the missing input supplies it (document control for the register, the welding engineer for a procedure), and the rule runs again.

      Closes

      When the rule has been evaluated, or the responsible engineer records with a reason that it does not apply. Never by being dismissed.

5. After a decision Every decision on the record; every correction on a copy.

   Each decision is recorded against its finding: accepted or rejected, the reason, the person, their role and the time. A rejection stays on the record, and the same question is not asked again until the element it was about changes.

   Where an accepted finding’s evidence determines the correction (finding 1: item 2 quantity to 5), the software proposes it as a markup on a copy and checks it again. The responsible engineer approves or declines it. The drawing owner then issues a new revision through configuration control, and that revision is reviewed in turn. A finding closes when its rule passes on an issued revision and a person confirms it.

6. Where it sits in the build An open review would hold VeldBuild’s configuration gate. A closed one releases nothing.

   Intended integration, described and not built. VeldBuild’s configuration gate asks which released revision governs a work package. A recorded review would be evidence on that gate.

   An undecided finding would hold the gate open: no work starts against a drawing still under review. A review whose basis has moved, because a cited drawing was re-issued, would make the gate unknown until the review runs again. A fully decided review would satisfy one condition and nothing more: the revision still has to be released, and the package’s other gates (material, predecessor work, access, quality, resources) still have to hold. A review could keep work from starting. It could never start it.

   The configuration gate on one work package, in VeldBuild

1. Geometry read wrongly

   What goes wrong

   A line read at the wrong position, or a dimension’s overridden text taken as its value. A misread raises a finding that is wrong, or hides one that is right.

   What the design does

   Every finding prints the values it read on both sheets beside its place, so a reviewer checks the reading against the drawing at a glance. A dimension whose printed text disagrees with what it measures is itself a finding. A region not read to a measured accuracy is cannot establish, never a finding.

   What remains

   A confident misread in a file format the reader was not tested on. Each format would be qualified on a fixed set of sheets before its files are accepted.

2. A rule that is wrong

   What goes wrong

   A rule encodes a requirement wrongly, or one that does not apply to this drawing type. It raises findings engineers reject one by one, or misses the case it was written for.

   What the design does

   Every rule has an owner at the yard and is tested before release on sheets it must flag and sheets it must pass. A rejection that says the rule is wrong goes to its owner. A review records the rules it ran, so changing a rule never quietly changes an old answer.

   What remains

   A rule wrong in a way no test sheet exercises. Only adjudicated use finds those.

3. A stale reference

   What goes wrong

   The sheet cites a drawing at a revision since superseded. Nothing on the sheet changed, so a comparison reports nothing.

   What the design does

   References are never judged from the sheet. The review reads the drawing register and records what it read and when. If a cited drawing is re-issued later, the answer becomes cannot establish until the review runs again. The earlier answer survives in the history; its authority does not.

   What remains

   A register that is itself wrong. The review can be no more current than the register document control keeps.

4. A reviewer who rubber-stamps

   What goes wrong

   A checker decides findings without opening them, because there are many and most are right. The record then says a person decided when nobody did.

   What the design does

   There is no accept-all. Each decision needs a reason, and the record shows whether the finding’s evidence was opened before it was decided. The person who accepts a finding cannot approve its correction. A yard can place a known fault in a copy under review to test whether its process finds it.

   What remains

   Diligence belongs to a person. The review can make its absence harder to hide; it cannot supply it.

5. A drawing built to mislead

   What goes wrong

   A file crafted to crash or exploit the reader, text hidden on a sheet to steer a model, a value under a fill, a layer hidden on screen that still prints.

   What the design does

   Every file is untrusted input, read in isolation. A file that cannot be read yields cannot establish for the whole sheet, never an empty review. Text on a drawing is data, never an instruction. Content the printed sheet does not show is itself a finding, because the floor works from the print.

   What remains

   A reader fault nobody has found yet. Isolation limits what one can reach; it does not prevent one.

6. Drawings that must not leave the yard

   What goes wrong

   Drawings carry a yard’s designs, and often its customer’s. A review that copies them to the wrong place is a breach, whatever it finds.

   What the design does

   A deployment holding real drawings would have to meet these requirements before reading one. None is claimed.

   • Each customer’s drawings stored apart, under keys only that customer’s deployment uses
   • No drawing ever reachable by a public link
   • Access granted per drawing package, at the least a role needs
   • No drawing content in any model’s context outside that customer’s own processing
   • Deleting a source deletes everything derived from it
   • Whether a deployment may hold export-controlled drawings is not established, and is decided per customer before any drawing is read

   What remains

   Each requirement would have to be shown to the customer’s own security reviewers. This page can only state them.

Why the newest drawing is not the governing one Which drawing governs when copies disagree