In plain terms: A 3D model can show what a ship looks like, but a picture alone
cannot prove a clearance, a thickness, or a clash result. Forge preserves the chain
from the source, whether that is an imported CAD file or geometry reconstructed
from drawings, to the number, the rule, the reviewer, and the final decision.
The difference between a picture and evidence
A 3D viewer is valuable for understanding location and context. It helps a reviewer see which compartment, component, or opening is being discussed. But the triangles used to draw a fast picture on a screen are an approximation of the engineering shape. Forge therefore keeps two related representations:
The display model helps people see the issue. The engineering geometry supplies the
evidence.
The evidence chain
1
1. Preserve the source
For an imported file, Forge records the file, its format, its digital fingerprint
(a hash that distinguishes that exact file version), its units, and how it entered
the system. For STEP assemblies, it also preserves each component occurrence and
its position in the assembly.For geometry reconstructed from drawings, the source is the drawing set itself.
Forge records which sheets and which regions of those sheets established the shape,
so a reconstructed component is traceable in exactly the same way an imported one
is. See From Drawings to a 3D Model.
2
2. Calculate from engineering geometry
A geometry kernel is the software that reads and calculates over the underlying CAD
shapes. It computes the requested result, such as a volume, a principal dimension,
or the clearance between two components.
3
3. Create a measurement record
Forge stores the result as a measurement record rather than passing around a loose
number. The record includes the value, unit, method, source model, import, and exact
geometry objects involved. This is applied to geometry.
4
4. Cite the measurement
Any formal claim such as “the clearance is 8 mm” must cite the identifier of that
measurement record. Forge can then verify that the record exists and belongs to the
same vessel and model scope.
5
5. Review and sign the decision
The cited claim moves through the verification ladder and responsible human review.
Once approved, the final decision preserves the evidence chain that supported it.
Clearance, contact, and clash
These terms sound similar but lead to different engineering actions:Clearance
A positive distance exists between two components. The stored result states the
distance, unit, measured objects, and source model.
Contact
The calculated clearance is zero: the components touch. Whether that is intended is
an engineering question, so the context remains visible.
Clash
The components overlap. Forge raises a review flag rather than inventing a negative
clearance or presenting an uncertain result as settled.
Evidence state travels with the geometry
In repair work the same model holds components of very different standing. A frame established clearly by two agreeing drawing sheets is not the same kind of object as one inferred from a single ambiguous profile, and neither is the same as a region that remains an open question. Forge keeps that standing attached to each component rather than flattening everything into one uniform-looking model. Selecting a part shows what supports it, what was assumed, which moment in the vessel’s life it describes, and what would have to be resolved to strengthen it. This is what makes the difference between a model you can plan a repair against and a model that merely looks complete.What happens when the source is uncertain
Imported CAD is not automatically authoritative. Units can be missing, scale can be ambiguous, and some files require repair before they can be read. Repair can also change the shape. Drawings carry their own version of this problem: a scanned sheet can be illegible in the region that matters, and two sheets can contradict each other. When that uncertainty could affect a measurement, Forge stops before creating the measurement record and identifies what needs review. Once the source or import question is resolved, the calculation can run from a known basis. This is an important trust behavior: Forge does not allow the precision of a displayed number to hide uncertainty in the model that produced it.Why this matters to different reviewers
Owners and program leaders
See whether readiness claims are supported by evidence and where review effort is
concentrated, without needing to inspect the model themselves.
Superintendents and port engineers
Move from a flagged issue to the exact components, measurement, model version, and
governing requirement behind it, while there is still time to plan around it.
Class surveyors and regulators
Follow a claim back through its cited measurement and source instead of receiving an
unexplained number or screenshot.
IT and security teams
Keep the source model and its evidence chain inside the approved environment, with
access and processing governed by sensitivity.