cross-validate

/cross-validate — IFC vs PDF Discrepancy Detection

Compare IFC model data against PDF schedules and generate a discrepancy report.

Step 1: Locate saved data

Check output/ for previously saved extraction files:

• IFC: output/ifc_*.json (prefer type-specific files)
• PDF: output/pdf_schedules_*.json (prefer over generic pdf_*.json)

Use the most recent file for each. If no data found, tell user to run /ifc-extract and /pdf-extract first.

Step 2: Cross-validate ONE element type at a time

Avoid context overflow. If user didn't specify a type, pick the first type with data in both sources.

Element matching

Normalise names: "D01" ↔ "Door 01" ↔ "D-01". Strip prefixes, separators, leading zeros. Case-insensitive.

Three finding states

State	Meaning	Example
MISMATCH	IFC says X, PDF says Y	IFC: FRL-30, PDF: FRL-60
ABSENT	IFC property null, PDF has value	IFC: FireRating null, PDF: FRL-60
PASS	Both sources agree	IFC: 47 doors, PDF: 47 rows

Checks to perform

1. Element count — IFC count vs PDF schedule row count
2. Properties — fire ratings, materials, dimensions per matched element
3. Fire rating wall/door compatibility — door in fire-rated wall must have matching rating (if wall data available)
4. Proxy elements — flag IfcBuildingElementProxy as INFO

ABSENT guidance

Likely cause: IFC export settings — "Export IFC common property sets" may not be enabled. Action: Architect should re-export with common property sets enabled.

Step 3: Generate report

Use this format:

## Discrepancy Report — <Project Name> — <YYYY-MM-DD>

### WARN: <Title>
- IFC Model: <value>
- PDF <Schedule> (p.<page>): <value>
- Action: <recommendation>

### PASS: <Title>
- IFC Model: <value>
- PDF <Schedule> (p.<page>): <value>

Order: WARN (MISMATCH) → WARN (ABSENT) → INFO → PASS

End with summary: total checks, PASS count, WARN count, INFO count.

Step 4: Save report

Save to output/discrepancy_<YYYY-MM-DD_HHMMSS>.md.

Critical Rules

1. NEVER do arithmetic. Use count field or array length from JSON data.
2. One element type at a time.
3. Use saved data only. Don't run extraction yourself — tell user to run /ifc-extract and /pdf-extract.
4. Distinguish MISMATCH from ABSENT. Different root causes, different remediation.
5. Every WARN must have an Action line.