Why AIA and LOIN matter for 3D models from imagery
Many projects start with a simple request: we have images and need a 3D model. That may be enough for visualization, but CAD, BIM, PV planning and as-built documentation need clearer information requirements.
DIN describes DIN EN ISO 19650 as a framework for defining, exchanging, versioning and organizing information. That logic is useful for photogrammetry projects even when the deliverable is not a full BIM model.
Voxelia processes supplied imagery into 3D models, point clouds, orthophotos, CAD traces, BIM-oriented models or viewers. Requirements make the delivery usable.
AIA, PIR, AIR and LOIN: the useful distinction
ISO 19650 distinguishes organizational, asset and project information requirements. For an as-built model, the key question is what decision the model must support.
AIA can be understood as client information requirements: what information is needed, when, at what quality and in which format.
LOIN defines the level of information need by purpose. ISO 7817-1:2024 strengthens this need-based approach internationally.
What to specify for a 3D as-built model from photos
A usable brief includes purpose, geometry requirements, semantic requirements and delivery format.
Referencing matters: local scale, reference measurements, GCPs, checkpoints, EPSG systems or a project origin determine whether CAD, GIS, Revit or PV tools can use the result.
Not every component needs the same information depth. Roof planes, facade axes, openings, terrain and context can each have different requirements.
| System / dataset | Suitability | Best for | Practical note |
|---|---|---|---|
| Viewer mesh | visual review | coordination and client approval | Useful for context, but not automatically CAD/BIM-ready. |
| E57/LAS/LAZ point cloud | geometry reference | Revit, AutoCAD, Archicad, scan-to-BIM | Needs clear coordinate, density, noise and control-point expectations. |
| Orthophoto / orthoplane | 2D measurement and CAD trace | roof and facade workflows | Projection type must match object geometry. |
| DXF/DWG | planning delivery | PV layouts, roof edges, facade lines | Requires clear layers, units, origin, scale and acceptance criteria. |
| BIM-oriented model | structured as-built | renovation, planning, digital twin | Component classes, attributes and LOIN must be defined upfront. |
A simple LOIN matrix for photogrammetry outputs
Small and medium as-built projects usually do not need an overloaded BIM specification. A compact matrix per component group is often enough.
Critical elements receive stronger geometry and data requirements; context remains mesh, point cloud or viewer data.
That keeps the model economical while protecting the planning decision.
Common mistakes in requirements for image-based as-built models
The most common mistake is a broad BIM target without a concrete decision.
The second mistake is confusing visual quality with measurable geometry.
The third is missing acceptance criteria.
| Risk scenario | Why it matters | Typical symptom | Countermeasure |
|---|---|---|---|
| Only file format specified | DXF, IFC or E57 do not define content | file opens but is not usable for planning | add purpose, components, scale, coordinates, layers and checks |
| Generic LOD instead of LOIN | one detail level ignores different needs | wrong areas receive the wrong effort | define LOIN per component group and decision |
| No referencing strategy | CAD/BIM/GIS need units, origin and coordinates | shifted or scaled imports | define EPSG, local origin, reference measures or GCP/checkpoint logic |
| Input imagery not reviewed | target requirements do not guarantee feasibility | gaps, noise or weak edges | perform intake review before promising the final delivery |
How Voxelia turns requirements into a usable delivery
Voxelia starts from the supplied imagery and the intended planning use, then defines the right delivery logic for 3D, CAD, BIM, orthophoto or viewer outputs.
Clarify decision and target system
PV planning, CAD measurement, BIM as-built, facade documentation, permit support, viewer or digital twin each need different data.
Review the image dataset
Sharpness, overlap, metadata, scale, references, perspectives and critical components are checked.
Set LOIN by component group
Roof, facade, openings, terrain, equipment and context are weighted by planning relevance.
Define delivery and acceptance
Formats, layers, units, coordinates, review views and quality documentation are aligned with the receiving workflow.
Sources and technical interpretation
The technical basis is DIN EN ISO 19650 for information management and ISO terminology around information requirements.
BIM Deutschland explains LOIN as information need depth. ISO 7817-1:2024 supports the need-based specification of information deliveries.
This article applies that BIM logic to Voxelia’s workflow: supplied photos and imagery are processed into planning-ready 3D, CAD, BIM, orthophoto or viewer deliverables.