A good-looking IFC can still be a bad delivery.

1. Model is far from the origin or rotated incorrectly

Symptoms: slow navigation, clipping, separated disciplines or a model that disappears when zooming to extents. Check: project coordinates, site placement, map conversion and units. Combine at least two discipline models before accepting the export.

2. Objects become generic proxies

Symptoms: walls, equipment or infrastructure objects arrive as IfcBuildingElementProxy. Check: export mapping, authoring category and selected IFC schema. A proxy may be intentional, but repeated standard objects usually indicate weak mapping.

3. Required properties are missing or empty

Symptoms: a property exists in the authoring model but not in IFC, or the property set name differs from the requirement. Check: export schedules, shared-parameter mapping, type versus occurrence storage, exact spelling and value data type.

4. Type and occurrence information is mixed

Symptoms: every door repeats the same type data, or a value that should differ per object is attached only to the type. Check: one object and its related type side by side. Decide where each requirement belongs before export.

5. Spaces are missing, duplicated or not bounded

Symptoms: absent rooms, zero areas, overlapping spaces or spaces assigned to the wrong storey. Check: room-bounding elements, phase and design option, export settings and the spatial containment tree.

6. Geometry is simplified, exploded or absent

Symptoms: missing openings, faceted curves, huge file size or objects without shape. Check: level of detail, tessellation, boolean failures, unsupported native features and whether linked models were included twice.

7. Duplicate objects appear after federation

Symptoms: doubled walls, grids or equipment. Check: linked model export, copy/monitor workflows, discipline responsibility and duplicate GUIDs. Compare source ownership before deleting anything.

8. Units or quantities are implausible

Symptoms: millimeters interpreted as meters, impossible areas or quantities that do not match geometry. Check: IFC unit assignment, project units, conversion factors and whether the quantity is calculated or manually supplied.

9. Wrong schema or exchange view

Symptoms: import rejection, missing entities or inconsistent results between tools. Check: the file header, project requirement, exporter documentation and the receiving application's supported schema and Model View Definition.

A repeatable pre-delivery workflow

1. Freeze the intended native-model revision.
2. Record exporter, schema and configuration.
3. Open the IFC in an independent viewer.
4. Check extents, orientation, storeys and spaces.
5. Inspect a sample of major object classes.
6. Run schema validation and project IDS checks.
7. Federate with another discipline.
8. Log failures by cause, owner and severity.
9. Re-export and repeat the same checks.