IfcOpenShell Validation Workflows

Quick Reference

Critical Warnings

• ALWAYS run ifcopenshell.validate.validate() with basic mode first (default express_rules=False). NEVER enable EXPRESS WHERE rules on a first pass — they are 10-100x slower on large models.
• ALWAYS pass a configured logging.Logger instance to validate(). The function logs results; it does NOT return them.
• NEVER assume a model is valid because validate() completes without raising an exception. Validation issues are logged, not raised. Use LogDetectionHandler or json_logger to detect issues programmatically.
• ALWAYS use ifctester for IDS (Information Delivery Specification) validation. ifcopenshell.validate checks schema compliance only — it does NOT check project-specific requirements.
• NEVER confuse schema validation with IDS validation. Schema validation verifies the IFC file structure is correct per EXPRESS schema. IDS validation verifies the IFC data meets project information requirements.
• ALWAYS call add_georeferencing before edit_georeferencing. The IfcMapConversion and IfcProjectedCRS entities MUST exist before editing.
• NEVER use IfcMapConversionScaled in IFC4 models. The scaled variant is only available in IFC4X3.
• ALWAYS check model.schema before applying version-specific validation logic. Georeferencing differs between IFC2X3 (property sets) and IFC4+ (dedicated entities).

Decision Tree: Which Validation Approach