Source assessment
Coverage, registration, point density, noise, occlusion, coordinate systems, and archive quality are considered before modelling.
Quality & standards
Quality defined by purpose, evidence, and agreed tolerance.
HBIM accuracy is not a single universal number. It depends on survey quality, the element being modelled, project use, representation method, and agreed scope.
Geometry rules
Rules for planes, curves, irregular surfaces, openings, wall thickness, and simplification are agreed for the intended use.
Model structure
Levels, categories, families, naming, views, parameters, and file organisation are checked before delivery.
Survey comparison
Selected model geometry can be visually or quantitatively compared with point-cloud evidence according to scope.
openBIM review
IFC exports are reviewed for intended exchange, including object categorisation and required properties where specified.
Delivery notes
Known limitations, excluded areas, assumptions, source conflicts, and unresolved questions can be documented transparently.
LOD / LOI / LOIN
Use requirements instead of vague detail labels.
A generic “LOD 300” request may not explain how an irregular historic cornice, deformed wall, collapsed area, or concealed structure should be represented.
For heritage work, the brief should define specific elements, geometric representation, information fields, tolerances, outputs, and intended uses. This produces a clearer and more defensible result.
A useful requirement states:
- Which elements must be modelled.
- Why the information is needed.
- How irregularity should be represented.
- What attributes and source notes are required.
- Which formats and views must be delivered.
- How acceptance will be checked.
Important: Model accuracy cannot exceed the quality and coverage of the source data. Areas hidden from the scanner, inaccessible, reflective, heavily vegetated, or insufficiently documented may require exclusions, assumptions, or additional survey work.
Need help defining an HBIM requirement?
Send the intended uses and available source data. PC2BIM can propose a practical model scope.