Information layer / category
Spatial Context and BIM Exchange
A model can look correct and still be wrong in scale, orientation, location, containment, or structured meaning. This category explains the information a recipient needs to interpret a CAD or BIM handoff and to state what the exchange is expected to preserve.
Overview
Start with the coordinate context: units, axes, origins, local frames, project frames, and the relationships that place one object or model relative to another. Then add georeferencing when project coordinates must be related to a map or survey reference system.
The BIM articles narrow the exchange further. An IFC release and model view identify a schema and purpose-bound scope; they do not prove that a particular application supports the requested route. Structured meaning—such as spatial containment, object relationships, classifications, and properties—must be requested separately from visible geometry. Information Delivery Specification (IDS) provides a way to express those requirements in a machine-interpretable form.
Articles
Read the articles in this order when you are defining or reviewing a handoff:
- Coordinate Context in CAD and BIM Exchange: Units, Axes, and Transform Chains — state the coordinate contract before interpreting position.
- Georeferencing a BIM Exchange Without False Alignment — connect local, project, and map context without treating visual overlap as proof.
- Define an IFC Exchange Scope: Release, Model View, and Purpose — replace “send an IFC” with a bounded request.
- When Geometry Arrives but BIM Meaning Does Not — identify semantic layers that a visible model may not retain.
- Turn BIM Information Needs into Exchange Requirements with IDS — make required objects, classifications, properties, values, and units explicit.
- Use a BIM Reference Model Without Confusing It for an Editable Source — set a safe boundary for coordination and reuse.
Where this category connects
Geometry and mesh fidelity are separate from spatial correctness. Product structure, engineering semantics, format and profile mechanics, ecosystem routes, transfer failures, and formal acceptance are handled by their respective portal categories. Use this category to define the spatial and BIM information that must survive; use those companion categories to investigate a representation, a named route, a failure, or an acceptance decision.
Reference notes
Articles in this layer
Coordinate Context in CAD and BIM Exchange: Units, Axes, and Transform Chains
A decision-oriented explanation of the coordinate information that must travel with a CAD or BIM handoff before position, orientation, and scale can be interpreted reliably.
Georeferencing a BIM Exchange Without False Alignment
How to specify the relationship among local coordinates, project coordinates, and a coordinate reference system so that a BIM exchange can be located and reused without relying on visual coincidence.
Define an IFC Exchange Scope: Release, Model View, and Purpose
A framework for turning “send an IFC” into a bounded exchange request with a declared release, model-view scope, intended recipient task, and information expectations.
When Geometry Arrives but BIM Meaning Does Not
A guide to recognizing when a visually usable model has lost the spatial structure, containment, relationships, classifications, or properties needed for BIM work.
Turn BIM Information Needs into Exchange Requirements with IDS
How to describe required BIM objects, classifications, properties, values, and units as an explicit exchange requirement instead of relying on an informal request for “a complete model.”
Use a BIM Reference Model Without Confusing It for an Editable Source
A practical boundary guide for using exchanged BIM as a coordination/reference model without assuming it retains authoring history, all semantics, or universal downstream suitability.