IFC-Claude-Skill-Package

Use when you need to understand or explain how the IFC schema is organized, decide which conceptual layer an entity belongs to, judge whether one schema is allowed to reference another, or work out why an entity does or does not carry a GlobalId. Prevents the upward-reference mistake (a lower-layer schema pointing at a higher-layer entity), the assumption that every IFC entity has a GUID, and the error of treating a serialized .ifc / .ifcXML / .ifcJSON file as the schema instead of a derived encoding. Covers the four-layer architecture (Resource, Core, Interoperability/Shared, Domain), the downward-only referencing rule (ladder principle), the EXPRESS schema as the single canonical model, and the GlobalId presence rule across IFC2x3, IFC4 and IFC4.3. Keywords: IFC layered architecture, four-layer schema, Resource layer, Core layer, Interoperability layer, Domain layer, ladder principle, downward reference, IfcKernel, IfcProductExtension, GlobalId, GUID, IfcRoot, EXPRESS canonical model, ISO 16739-1, ISO 10303

Use when authoring a new IFC file from scratch and the minimal valid skeleton must be built before any element can be added: the IfcProject context root, the IfcUnitAssignment, the IfcGeometricRepresentationContext, the spatial tree, the IfcOwnerHistory, the STEP header, and the first wall with geometry. Prevents the file failing to open or showing nothing in a viewer because units, the geometric context, or the spatial root are missing, because GlobalId values are regenerated on every export, or because FILE_SCHEMA does not match the entities used. Covers the mandatory setup sequence, the HEADER and FILE_SCHEMA, stable GlobalId generation, the project to site to building to storey chain wired with IfcRelAggregates, placing one IfcWall with IfcRelContainedInSpatialStructure, and the decision of which IFC version to target. Keywords: author IFC file, create IFC from scratch, minimal IFC file, IfcProject setup, IfcUnitAssignment, IfcOwnerHistory, IfcGeometricRepresentationContext, FILE_SCHEMA, GlobalId generati

Use when producing, reading, or extracting COBie facility-management handover data from an IFC model: mapping COBie worksheets to IFC entities, deciding which records belong in COBie scope, choosing between the IFC STEP exchange and the spreadsheet form, or extracting a COBie subset from a full design model. Prevents treating COBie as a geometry format, inventing IFC entity names for COBie records, mapping a Component to a type instead of an occurrence, and exporting parametric geometry into an FM handover. Covers COBie as the Basic FM Handover MVD subset, the worksheet to IFC entity map, the IFC2x3 and IFC4 bindings, and the STEP versus spreadsheet exchange. Keywords: COBie, FM handover, facility management handover, Basic FM Handover MVD, asset management data, IfcSpace, IfcZone, IfcSystem, IfcTask, IfcDocumentReference, IfcConstructionResource, COBie spreadsheet, COBie worksheet, component versus type, asset register from IFC, handover data, how do I export COBie, what is COBie, COBie data missing, non-gra

Use when choosing which IFC implementation library to use for a project, or when unsure which tool reads and writes IFC files for a given language, platform, or target IFC version. Prevents picking a library that does not fit the language or platform, expecting this package to teach a library API, asserting an unverified IFCx Rust library, and confusing schema migration with geometry conversion. Covers the library landscape (IfcOpenShell, web-ifc, xBIM, IFC++), the language and platform decision matrix, routing to the owning OpenAEC skill packages, and the emerging state of IFC5 and IFCx tooling. Keywords: IFC library, IfcOpenShell, web-ifc, ThatOpen engine_web-ifc, xBIM, XbimEssentials, IFC++, ifcx-rs, which IFC library should I use, read IFC in Python, parse IFC in the browser, IFC in dotnet, IFC in Rust, IFC WASM, library decision matrix, pointer skill, which tool for IFC, how do I open an IFC file in code, "library does not support my IFC version", "no IFC library for my language", "IFC parsing is too slo

Use when reading, generating, or evaluating an ifcJSON file, choosing a JSON encoding for IFC data in a web or REST application, or resolving the ref-based cross-references in an ifcJSON document. Prevents treating ifcJSON as a stable standardized format, expecting lossless round-tripping, inlining referenced entities instead of using ref objects, and using the legacy IFCJSON-Team lineage instead of the current buildingsmart-community repo. Covers ifcJSON as a provisional candidate format for IFC4 and IFC4.3 : the top-level envelope, the data array of entity objects, camelCased attribute keys, the ref object that replaces the STEP id, file size, and the two ifcJSON lineages. Keywords: ifcJSON, IFC JSON, JSON encoding of IFC, ifcjson data array, ref object, globalId, camelCase IFC attributes, buildingsmart-community ifcJSON, provisional format, candidate format, IFC for web apps, IFC REST API, how do I read an IFC JSON file, convert IFC to JSON, IFC without EXPRESS, my ifcJSON will not round-trip, "ifcJSON fil

Use when you need to read, write, or recognise an ifcXML file, understand the iso_10303_28 / uos document structure, or resolve id / ref / href references in IFC XML data. Prevents confusing ifcXML (ISO 10303-28) with the STEP Physical File (ISO 10303-21), hand-authoring the XSD instead of generating it, ignoring the version-specific Part 28 configuration file, and mishandling the by-reference versus by-containment duality. Covers the ifcXML XML encoding, ISO 10303-28, the Part 28 configuration file, the iso_10303_28 root and single uos element, entity-to-element mapping, id / ref / href references, and when to choose ifcXML over SPF. Keywords: ifcXML, .ifcXML, IFC XML, ISO 10303-28, Part 28 configuration file, iso_10303_28, uos, unit of serialization, id ref href, xsi:nil, by-reference, by-containment, XSD validation, XSLT, XPath, how do I open an ifcXML file, ifcXML vs ifc, what is ifcXML, IFC XML schema, ifcXML file too large, "ifcXML will not validate", "href reference not resolving", "ifcXML opened as pl

Use when asked to migrate an IFC file to another schema version, upgrade an IFC2x3 model to IFC4 or IFC4.3, downgrade an IFC4 model, or plan a schema-version conversion of an IFC dataset end to end. Prevents copying attributes blindly across a version boundary, silently dropping non-migratable entities, downgrading when an upgrade was the real goal, confusing geometry conversion with schema migration, and declaring a migration done without revalidating the result. Covers the migration workflow as an orchestration : source-schema detection, direction choice, the two-stage entity-then-attribute remap, the non-migratable-entity ledger, the ifcpatch Migrate recipe, and post-migration validation, across IFC2x3, IFC4 and IFC4.3. Keywords: IFC version migration, migrate IFC file, upgrade IFC2x3 to IFC4, IFC4 to IFC4.3, downgrade IFC, schema conversion, ifcpatch Migrate recipe, entity map, attribute map, IfcWallStandardCase deprecated, IfcBuildingElement renamed IfcBuiltElement, IfcBuildingSystem IfcBuiltSystem, non-

Use when an IFC file is schema-valid but you must judge whether it is actually useful, audit an IFC model for information completeness, score model quality before handover, or answer why a valid IFC file is empty in facility management, quantity take-off, or analysis software. Prevents confusing schema validity with information completeness, declaring a model "good" because it passed validation, auditing project-specific demands that belong to IDS, and shipping a model whose elements carry no properties, materials, classifications, quantities, or georeferencing. Covers a cross-skill model-quality audit across seven completeness dimensions (spatial containment, property sets, geometry representation, materials, classifications, quantities, georeferencing), a deterministic weighted scoring rubric, the validity-versus-completeness-versus-IDS three-tier model, and routing each gap to the owning skill, across IFC2x3, IFC4 and IFC4.3. Keywords: IFC quality check, IFC model audit, information completeness, model qua

Use when asked to validate an IFC file, check whether an IFC model is conformant, run a pre-delivery quality gate on an IFC file, decide if an IFC file is valid, or triage a buildingSMART validation report. Prevents skipping the STEP-syntax gate, treating a warning as a file-invalidating error, reading a hidden pass as a skipped check, validating against the wrong schema, and confusing schema conformance with project information requirements. Covers the buildingSMART five-stage validation pipeline (STEP syntax, schema, normative, industry practice, bSDD), the Gherkin functional-part coverage map, the fifteen-item anti-pattern checklist, finding triage by severity, and routing each fault class to the matching ifc-errors skill, across IFC2x3, IFC4 and IFC4.3. Keywords: validate IFC file, is my IFC file valid, IFC validation pipeline, buildingSMART validation service, IFC conformance check, validation report triage, pre-delivery quality gate, schema validation, Gherkin normative rules, implementer agreement, inf

Use when authoring a complete, coordinated IFC model from scratch and you need the correct build order, or when an IFC file you produced is rejected, opens empty in a viewer, or loses its elements, properties or geometry downstream. Prevents adding elements before the project skeleton exists, skipping units or representation contexts, wiring the spatial tree with the wrong relationship, attaching geometry with no context, and declaring a model done without validating it. Covers the end-to-end authoring sequence (version and MVD decision, STEP header, IfcProject, units, representation contexts, owner history, spatial tree, elements, geometry, placement, properties, materials, classifications), which syntax and impl skill owns each step, the IFC2x3 versus IFC4 versus IFC4.3 differences that change the build, and the self-check before delivery. Keywords: IFC model authoring, build a complete IFC file, IfcProject setup, IfcUnitAssignment, IfcGeometricRepresentationContext, spatial structure, IfcRelAggregates, Ifc

Use when an IFC file is rejected at the STEP-syntax stage of validation, a parser reports a string or header error, accented or non-ASCII text shows up as garbage characters, or the file fails before any schema check runs. Prevents writing an un-doubled apostrophe or backslash inside a STEP string, breaking a \X2\ or \X4\ escape with a missing \X0\ terminator, shipping mojibake from a UTF-8 versus Latin-1 mismatch, sending a malformed FILE_DESCRIPTION, FILE_NAME, or FILE_SCHEMA header, and hunting for a non-existent IfcFileDescription entity. Covers STEP Physical File string escaping failure modes, the three header entities and their EXPRESS, the empty-description rejection, a missing or lowercase FILE_SCHEMA identifier, a byte-order mark before the magic token, and why a stage-1 STEP syntax error blocks the file before schema validation. Keywords: IFC encoding error, STEP syntax error, string escaping, \X2\, \X4\, \X0\ terminator, doubled apostrophe, mojibake, character encoding mismatch, UTF-8, Latin-1, FIL

Use when an IFC file fails validation on a property set, quantity set or material association, or when a custom property set is rejected, ignored, or collides with the standard library, or a layered-material assignment breaks a WHERE rule. Prevents naming a custom property set with the reserved Pset_ prefix, pointing IfcRelDefinesByProperties at a type object, attaching IfcMaterialLayerSetUsage to a type instead of an occurrence, hand-writing the derived TotalThickness, putting a length unit on an area quantity, and leaving IfcMaterialList in a new IFC4 file. Covers the Pset_ and Qto_ naming conventions, the NoRelatedTypeObject WHERE rule, the occurrence-only rule for material usage entities, derived attributes, quantity unit-type WHERE rules, and the IfcMaterialList legacy smell, across IFC2x3, IFC4 and IFC4.3. Keywords: property set error, Pset_ prefix, custom property set, IfcPropertySet, IfcRelDefinesByProperties, NoRelatedTypeObject, attach Pset to type, quantity set, IfcElementQuantity, Qto_ prefix, Ifc

Use when an IFC file has a reference that points nowhere, a parser crashes on an unresolved #id, or an element silently disappears from a downstream tool (no material, no property set, no spatial location) even though the file is schema-valid. Prevents treating a dangling #id and a missing INVERSE link as the same bug, trusting a "valid" verdict to mean the model is complete, and creating a relationship with the Relating and Related roles swapped. Covers the reference-graph nature of the STEP instance model, dangling and wrong-typed #id references, missing IfcRel* relationship entities, why a missing INVERSE attribute is a silent failure, detection scans, and fixes, across IFC2x3, IFC4 and IFC4.3 including the IfcBuildingElement to IfcBuiltElement rename. Keywords: dangling reference, broken #id, unresolved reference, missing INVERSE link, IfcRelContainedInSpatialStructure, IfcRelAssociatesMaterial, IfcRelDefinesByProperties, orphan element, element has no material, element has no property set, element not in

Use when an IFC model loads blank in a viewer, geometry is missing, garbled, off-scale, mispositioned, or silently dropped on import, or a buildingSMART validation report flags a GEM rule. Prevents shipping shape representations with no representation context, placement chains that mix 2D and 3D, non-watertight Breps, degenerate or duplicated geometry, and geometry that the declared MVD forbids. Covers GEM051 and GEM052 missing or wrong context, IfcLocalPlacement chain errors and dimension mismatch, IfcFacetedBrep watertight-shell rules, GEM111, GEM112 and GEM113 duplicated and colinear points, zero-area faces and non-manifold solids, and MVD geometry mismatch across IFC2x3, IFC4 and IFC4.3. Keywords: IFC geometry error, nothing shows in viewer, blank model, empty model, model off by 1000x, geometry dropped on import, GEM051, GEM052, GEM111, GEM112, GEM113, representation context missing, IfcGeometricRepresentationContext, invalid placement chain, non-watertight shell, non-manifold solid, zero-area face, dege

Use when IFC elements do not appear in a viewer's model tree, are missing from quantity take-off or facility-management exports, or a buildingSMART validation report flags spatial-structure problems : orphan elements with no spatial container, one element contained in two places at once, an element placed at the wrong spatial level, a deprecated proxy used as a placeholder, or a missing or broken spatial tree. Prevents shipping orphan elements with no IfcRelContainedInSpatialStructure link, mislabelling double containment as a WR31 violation, attaching physical elements with IfcRelAggregates instead of IfcRelContainedInSpatialStructure, using IfcBuildingElementProxy as a void or clearance placeholder in IFC4.3, and building a spatial tree that never reaches IfcProject. Covers orphan-element detection, the IfcElement.ContainedInStructure SET [0:1] inverse, WR31 and WR41, the IfcProject NoDecomposition rule, the IfcSingleProjectInstance global rule, IfcRelReferencedInSpatialStructure for multi-storey elements,

Use when an IFC file fails validation because the declared FILE_SCHEMA does not match the entities used, when a file written for one schema is read with another schema's expectations, or when a model uses an entity that is deprecated or removed for its declared version. Prevents writing IfcBuildingElement into an IFC4.3 file, declaring IFC4 in the header while using IFC2x3-only entities, assuming OwnerHistory is mandatory in IFC4, copying DERIVED attribute slots blindly during migration, and treating a legacy IfcMaterialList as a hard error. Covers the FILE_SCHEMA token per version, the hard renames between IFC2x3, IFC4 and IFC4.3, deprecated and removed entities per version, attribute optionality and type changes across versions, the DERIVED attribute asterisk trap, and how to detect version inconsistency in an existing file. Keywords: IFC version mismatch, FILE_SCHEMA, IFC2X3, IFC4, IFC4X3_ADD2, deprecated entity, removed entity, IfcBuildingElement, IfcBuiltElement, IfcWallStandardCase, StandardCase removed

Use when an IFC file fails schema validation or a buildingSMART validation report shows errors, and the cause is a WHERE-rule break, a global-rule break, an abstract-entity instantiation, a cardinality violation, or a wrong attribute type. Prevents instantiating an abstract supertype, calling an IFC4.3 IfcBuiltElement instantiation a schema error, ignoring the warning-vs-error distinction, and reading a validation report as if hidden passes were missing checks. Covers EXPRESS WHERE rules and global RULEs, abstract supertypes per version, attribute cardinality and type errors, the buildingSMART validation pipeline and its severities, the Gherkin normative-rule layer, running a single Gherkin rule locally, and Implementer Agreements versus Informal Propositions. Keywords: IFC schema validation, WHERE rule violation, global rule, abstract entity, IfcBuildingElement, IfcBuiltElement, cardinality, wrong attribute type, buildingSMART validation service, Gherkin rules, implementer agreement, informal proposition, "f

Use when exporting an IFC file that must conform to a Model View Definition (MVD): choosing between Coordination View 2.0, Reference View, and Design Transfer View, declaring the matching ViewDefinition string in FILE_DESCRIPTION, and restricting the geometry to the representation types the chosen view permits. Prevents the non-conformant export that declares ReferenceView_V1.2 but still emits CSG or Boolean-clipping geometry, the file that names an MVD whose IFC version does not match FILE_SCHEMA, and the export that fails buildingSMART certification because the ViewDefinition contract is broken. Covers what an MVD constrains, the geometry matrix per view, the ViewDefinition keyword syntax, the Reference-versus-Design-Transfer subset relationship, and the software certification and Validation Service context. Keywords: MVD export, Model View Definition, ViewDefinition, FILE_DESCRIPTION, Coordination View 2.0, Reference View, Design Transfer View, ReferenceView_V1.2, CoordinationView_V2.0, DesignTransferView,

Use when adding descriptive data to elements that already exist in an IFC model: attaching a property set, an element quantity, a material, or a classification reference, without touching geometry or spatial structure. Prevents pointing IfcRelDefinesByProperties at a type object, putting a material usage entity on a type instead of an occurrence, naming a custom property set with the reserved Pset_ prefix, conflating quantities with properties, and duplicating one relationship per element. Covers the occurrence versus type attachment split, the HasPropertySets type mechanism, IfcRelAssociatesMaterial set-on-type usage-on-occurrence, IfcRelAssociatesClassification, and the Pset_ and Qto_ naming rules. Keywords: IFC enrichment, attach property set, IfcRelDefinesByProperties, IfcPropertySet, HasPropertySets, IfcElementQuantity, attach material, IfcRelAssociatesMaterial, IfcMaterialLayerSet, IfcMaterialLayerSetUsage, IfcRelAssociatesClassification, IfcClassificationReference, Pset_ prefix, Qto_ prefix, type versu

Use when converting an IFC model between encodings (SPF .ifc, ifcXML, ifcJSON, ifcZIP) and the result must stay faithful, and when deciding which on-disk format to pick for a given exchange. Prevents confusing a format transcode with a schema-version migration, expecting STEP #id numbers to survive a round-trip, treating ifcJSON as a guaranteed lossless format, and assuming DERIVE or INVERSE attributes are lost in conversion. Covers the format comparison matrix, the EXPRESS schema as the single canonical model, SPF to ifcXML conversion (ISO 10303-28 plus the Part 28 configuration file), SPF or ifcXML to ifcJSON (provisional), ifcZIP wrapping, what is and is not preserved, and the transcoding vs version-migration vs geometry-export split. Keywords: IFC format conversion, transcoding, SPF to ifcXML, ifc to json, ifcXML, ifcJSON, ifcZIP, ISO 10303-28, Part 28 configuration file, lossless, round-trip, "which IFC format", "convert ifc file", "ifc file too big", "json instead of ifc", "lost data after conversion",

Use when extracting the geometry of an IFC element from an existing file in order to render it, mesh it, or measure it: resolving IfcProduct.Representation to its shape items, picking the right representation, walking the IfcLocalPlacement chain to a world transformation matrix, and decoding each RepresentationType (SweptSolid, Brep, Tessellation, CSG/Clipping, MappedRepresentation). Prevents every extracted element piling up at the origin because the placement chain was skipped, a blocky model because the Box representation was read instead of Body, scrambled meshes from treating IFC indices as zero-based, empty geometry because IfcMappedItem instances were not resolved, and wrong volumes from treating a tessellated approximation as an exact solid. Covers the product-to-shape resolution path, RepresentationIdentifier and RepresentationType, the placement-to-matrix computation, mapped-item transforms, and the IFC2x3 versus IFC4 versus IFC4.3 differences. Keywords: extract IFC geometry, IfcShapeRepresentation,

Use when migrating an IFC model between schema versions (IFC2x3, IFC4, IFC4.3) and the migrated file fails schema validation, opens with shifted or corrupt attributes, or still contains entities the target schema deleted. Prevents blind positional attribute copying, regex find-and-replace migration, leaving deleted entities in the file, confusing geometry conversion with schema migration, and trusting an unvalidated result. Covers the two-stage entity-then-attribute remap, the verified IFC2x3 to IFC4 and IFC4 to IFC4.3 entity and attribute changes, upgrade versus downgrade asymmetry, identity preservation, and the mandatory validation gate. Keywords: IFC version migration, schema migration, IFC2x3 to IFC4, IFC4 to IFC4.3, FILE_SCHEMA, IfcBuildingElement IfcBuiltElement rename, StandardCase removed, IfcProxy deleted, entity mapping, attribute mapping, ifcpatch Migrate, IfcConvert, upgrade downgrade, migrated file invalid, attributes shifted after migration, how do I convert IFC version, why does my migrated IF

Use when reading property sets, quantities, or effective attribute values out of an IFC model and the extracted values look wrong, incomplete, empty, or missing. Prevents reading only occurrence property sets while ignoring inherited type defaults, using IsDefinedBy to reach the type in IFC4 and IFC4.3, treating an IfcElementQuantity as an IfcPropertySet, and forgetting to expand an IfcPropertySetDefinitionSet bundled inside one relationship. Covers the IsDefinedBy / IsTypedBy traversal, the type vs occurrence override resolution algorithm, reading IfcElementQuantity, resolving a property value unit, IfcPropertySetDefinitionSet expansion, standard Pset_ vs custom property sets, and the IFC2x3 vs IFC4 inverse-attribute split. Keywords: property extraction, read property set, IfcRelDefinesByProperties, IsDefinedBy, IsTypedBy, HasPropertySets, IfcElementQuantity, IfcPropertySet, type vs occurrence override, Pset_WallCommon, quantity takeoff, NominalValue, resolve unit, "property is missing", "value is empty", "w

Use when reading or parsing an IFC STEP physical file: indexing instances, resolving #id references, dispatching on FILE_SCHEMA, reading positional attributes, or traversing the entity graph from an element to its relationships. Prevents resolving references in a single pass and failing on forward references, expecting INVERSE attributes to be stored in the file, miscounting positional attribute slots when $ or * appear, skipping the FILE_SCHEMA dispatch, and looking for a wall's properties as a direct attribute. Covers the two-pass parse, the instance line grammar, the $ and * tokens, building the inverse index, and navigating IsDefinedBy, IsTypedBy, ContainedInStructure, and HasAssociations. Keywords: IFC parser, parse IFC file, read .ifc file, STEP physical file, SPF, FILE_SCHEMA, two-pass parse, forward reference, #id reference, instance index, INVERSE attribute, IsDefinedBy, IsTypedBy, ContainedInStructure, HasAssociations, IfcRelDefinesByProperties, positional attributes, dollar token, asterisk token, p

Use when authoring an IFC file and you must build the spatial breakdown tree and place every physical element into it, or when a wall, slab, or door does not show up in a viewer because it has no storey. Prevents orphan elements, double containment, placing elements with IfcRelAggregates instead of IfcRelContainedInSpatialStructure, and reversing the Relating and Related roles. Covers the top-down build order, IfcRelAggregates wiring, single-container placement, IfcRelReferencedInSpatialStructure for multi-storey elements, the IFC4.3 IfcFacility and IfcFacilityPart tree, and the orphan-check verification step. Keywords: IfcRelAggregates, IfcRelContainedInSpatialStructure, IfcRelReferencedInSpatialStructure, IfcProject, IfcSite, IfcBuilding, IfcBuildingStorey, IfcSpace, IfcFacility, IfcFacilityPart, spatial decomposition, spatial breakdown, build the spatial tree, place element in storey, orphan element, element not in viewer, wall has no storey, element missing from model, how do I add a wall to a storey, mul

Use when you need to model or read an IFC solid as boundary representation, CSG, or a clipping operation : faceted and advanced Breps, the shell / face / loop topology, Boolean results, CSG primitives, and half-space clipping of extruded elements. Prevents a non-watertight shell, a repeated first point in a poly-loop, a mixed loop-type shell, a clipping result with the wrong operator, a finite solid used as a clip, and a RepresentationType that does not match the item. Covers IfcManifoldSolidBrep, IfcFacetedBrep, IfcFacetedBrepWithVoids, IfcAdvancedBrep, IfcAdvancedBrepWithVoids, IfcClosedShell, IfcOpenShell, IfcFace, IfcFaceOuterBound, IfcAdvancedFace, IfcPolyLoop, IfcEdgeLoop, IfcBooleanResult, IfcBooleanClippingResult, IfcHalfSpaceSolid, IfcPolygonalBoundedHalfSpace, IfcCsgSolid, the IfcCsgPrimitive3D family, and IFC2x3 / IFC4 / IFC4.3 differences. Keywords: IFC Brep, boundary representation, IfcFacetedBrep, IfcAdvancedBrep, IfcClosedShell, IfcPolyLoop, watertight mesh, IfcBooleanClippingResult, clipping,

Use when you need to build, read, or debug parametric solid geometry in an IFC model : extruding a profile into a wall or slab, revolving a profile into an arch, sweeping a profile along a curve, or modelling a pipe or rebar as a swept disk, and when deciding the RepresentationType label for the shape. Prevents feeding a CURVE-type (open) profile into a solid sweep, an extrusion direction perpendicular to Z, a revolution axis outside the XY plane, an unbounded directrix with no parameters, an InnerRadius larger than the Radius, and mislabelling an advanced sweep as plain SweptSolid. Covers IfcSweptAreaSolid, IfcExtrudedAreaSolid, IfcRevolvedAreaSolid, IfcExtrudedAreaSolidTapered, IfcRevolvedAreaSolidTapered, IfcDirectrixCurveSweptAreaSolid, IfcSurfaceCurveSweptAreaSolid, IfcFixedReferenceSweptAreaSolid, IfcSweptDiskSolid, the SweptArea / Position / ExtrudedDirection / Depth / Axis / Angle / Directrix / Radius attributes, the WHERE rules, the SweptSolid versus AdvancedSweptSolid mapping, and IFC2x3 / IFC4 / IF

Use when you need to author, read, or debug tessellated (faceted) geometry in an IFC4 or IFC4.3 model : triangle meshes and polygon meshes built from a shared indexed point pool, the lightweight geometry that the Reference View MVD relies on. Prevents the tessellation errors that break meshes : 0-based instead of 1-based indices, a triangle row with the wrong number of indices, a PnIndex indirection applied twice, a Closed flag that lies about whether the mesh is a solid, and using tessellation entities in an IFC2x3 file where they do not exist. Covers IfcCartesianPointList3D and IfcCartesianPointList2D, IfcTessellatedFaceSet, IfcTriangulatedFaceSet (Coordinates, Normals, Closed, CoordIndex, PnIndex), IfcPolygonalFaceSet, IfcIndexedPolygonalFace, IfcIndexedPolygonalFaceWithVoids, the PnIndex indirection layer, the RepresentationType Tessellation mapping, and the IFC4 / IFC4.3 version differences. Keywords: IFC tessellation, IfcTriangulatedFaceSet, IfcPolygonalFaceSet, IfcTessellatedFaceSet, IfcCartesianPointL

Use when you need to anchor an IFC model to real-world geographic coordinates : declare where the local project origin sits on Earth, rotate the model onto a map grid, pick between coarse site latitude/longitude and a precise projected CRS, or place infrastructure objects along an alignment by station and offset. Prevents treating the coarse IfcSite latitude as precise georeferencing, applying the map-conversion translation and rotation in the wrong order, mixing signs in a compound plane angle, targeting a map conversion at a non-projected CRS, emitting IFC4 or IFC4.3 georeferencing entities into an IFC2x3 file, and authoring geometry at raw projected coordinates. Covers IfcSite RefLatitude / RefLongitude / RefElevation, IfcCompoundPlaneAngleMeasure, IfcMapConversion, IfcProjectedCRS, IfcCoordinateReferenceSystem, IfcCoordinateOperation, IfcMapConversionScaled, the IFC4.3 IfcLinearPlacement family, the LoGeoRef levels, and the IFC2x3 / IFC4 / IFC4.3 version differences. Keywords: IFC georeferencing, IfcMapCo

Use when you need to create, place, or debug a physical construction element in an IFC model : a wall, slab, beam, column, member, plate, door, window, roof, covering, stair, railing, footing, or proxy, including the type object, the PredefinedType enumeration, the spatial containment link, and the opening / void / fill triad for a door or window in a wall. Prevents using the removed name IfcBuildingElement in an IFC4.3 file (it was renamed IfcBuiltElement), leaving an element orphaned with no spatial container, reversing the IfcRelVoidsElement and IfcRelFillsElement anchors, setting PredefinedType to USERDEFINED without an ObjectType, and using a deleted *StandardCase entity. Covers IfcWall, IfcSlab, IfcBeam, IfcColumn, IfcMember, IfcPlate, IfcDoor, IfcWindow, IfcRoof, IfcCovering, IfcStair, IfcRailing, IfcFooting, IfcBuildingElementProxy, the matching type objects and PredefinedType enums, IfcOpeningElement, IfcRelContainedInSpatialStructure, IfcRelVoidsElement, IfcRelFillsElement, the IFC4.3 infrastructure

Use when you need to position an IFC product in space, build or read the placement tree, or resolve an element to world coordinates : the door placed relative to its wall, the wall relative to its storey, the storey relative to the building, and so on up to the project world coordinate system. Prevents the placement errors that put elements in the wrong spot : a 3D placement chained to a 2D parent, a circular PlacementRelTo reference, supplying only one of Axis and RefDirection, forgetting to multiply the whole chain, and confusing the local geometry origin with the world position. Covers IfcObjectPlacement, IfcLocalPlacement (PlacementRelTo chaining and RelativePlacement), IfcAxis2Placement3D and IfcAxis2Placement2D with the right-handed axis derivation, IfcCartesianPoint, IfcDirection, IfcGridPlacement and IfcVirtualGridIntersection, and the IFC2x3 / IFC4 / IFC4.3 version differences. Keywords: IFC placement, IfcObjectPlacement, IfcLocalPlacement, PlacementRelTo, RelativePlacement, IfcAxis2Placement3D, IfcA

Use when you need to define, choose, or debug a 2D cross-section profile in an IFC model : a rectangle or circle profile, a standard steel section (I, L, U, T, C, Z), a hollow section, an arbitrary free-form outline, a profile with holes, or a composite or derived profile. Prevents feeding a CURVE-type or open profile into a solid sweep, using an IfcLine as a profile boundary, declaring a hollow wall thicker than its radius, nesting a composite profile inside another composite, and mixing AREA and CURVE profiles in one composite. Covers IfcProfileDef and IfcProfileTypeEnum, IfcParameterizedProfileDef and the eleven concrete parameterized profiles, IfcArbitraryClosedProfileDef, IfcArbitraryOpenProfileDef, IfcArbitraryProfileDefWithVoids, IfcCompositeProfileDef, IfcDerivedProfileDef, and the IFC2x3 / IFC4 / IFC4.3 version differences. Keywords: IFC profile, IfcProfileDef, IfcProfileTypeEnum, AREA, CURVE, IfcParameterizedProfileDef, IfcRectangleProfileDef, IfcCircleProfileDef, IfcIShapeProfileDef, IfcLShapeProfi

Use when you need to attach geometry to an IFC product, read a model's shape data, or debug why a representation is rejected : the product-to-shape chain, IfcShapeRepresentation, the RepresentationIdentifier and RepresentationType value tables, the Model representation context and its sub-contexts, topology representations, named shape aspects, and mapped (instanced) geometry. Prevents a shape representation with no placement, a non-shape-model entity inside IfcProductDefinitionShape, a missing or mismatched RepresentationType, a sub-context with literal instead of derived attributes, and a self-referential mapped item. Covers IfcProduct.Representation, IfcProductRepresentation, IfcProductDefinitionShape, IfcShapeRepresentation, IfcTopologyRepresentation, IfcGeometricRepresentationContext, IfcGeometricRepresentationSubContext, IfcGeometricProjectionEnum, IfcShapeAspect, IfcRepresentationMap, IfcMappedItem, IfcCartesianTransformationOperator, IfcRepresentationItem, and IFC2x3 / IFC4 / IFC4.3 version difference

Use when you need to attach a classification code (Uniclass, OmniClass, MasterFormat, ETIM) or an external library reference to objects in an IFC model, or read and debug the classification and library entities of an existing model. Prevents putting the code in the wrong attribute, inventing IFC entity names, using the IFC2x3 attribute name in an IFC4 file (ItemReference vs Identification, Location vs Specification), and confusing the classification system entity with a single classification code. Covers IfcClassification, IfcClassificationReference, IfcRelAssociatesClassification, the IfcClassificationSelect and IfcClassificationReferenceSelect select types, the library entities IfcRelAssociatesLibrary, IfcLibraryReference and IfcLibraryInformation, the external systems Uniclass 2015 / OmniClass / MasterFormat / ETIM, and the IFC2x3 / IFC4 / IFC4.3 version differences. Keywords: IFC classification, IfcClassification, IfcClassificationReference, IfcRelAssociatesClassification, IfcClassificationSelect, IfcClas

Use when you need to assign, read, or debug materials on IFC elements : a plain named material, a layered build-up for a wall or slab, a profiled cross-section for a beam or column, a constituent set for a window or door, or material properties. Prevents the most common material errors : attaching a layer-set or profile-set usage to a type object instead of an occurrence, manually serializing the derived TotalThickness, writing IfcMaterialList in a new IFC4 file, and using the deleted IFC2x3 material-property subtypes. Covers IfcMaterial, IfcRelAssociatesMaterial, the IfcMaterialSelect abstraction, the layered family (IfcMaterialLayerSet / IfcMaterialLayer / IfcMaterialLayerSetUsage), the profiled family (IfcMaterialProfileSet / IfcMaterialProfile / IfcMaterialProfileSetUsage / IfcCardinalPointReference), the constituent family (IfcMaterialConstituentSet / IfcMaterialConstituent), legacy IfcMaterialList, IfcMaterialProperties, and IFC2x3 / IFC4 / IFC4.3 version differences. Keywords: IFC materials, IfcMateria

Use when you need to attach, read, or debug non-geometric properties on an IFC element : a property set, the relationship that binds it, the six simple property value types, complex (nested) properties, how a property resolves to a unit, and the Pset_ naming convention. Prevents pointing IfcRelDefinesByProperties at a type object (the NoRelatedTypeObject rule), giving two properties the same Name in one set, naming a custom property set with the reserved Pset_ prefix, and picking the wrong IfcSimpleProperty subtype for a value. Covers IfcPropertySet, IfcRelDefinesByProperties, IfcRelDefinesByType, the IfcProperty tree, IfcPropertySingleValue, IfcPropertyEnumeratedValue, IfcPropertyBoundedValue, IfcPropertyListValue, IfcPropertyTableValue, IfcPropertyReferenceValue, IfcComplexProperty, IfcPropertySetTemplate, type vs occurrence override, and IFC2x3 / IFC4 / IFC4.3 version differences. Keywords: IFC property set, Pset, IfcPropertySet, IfcRelDefinesByProperties, IfcProperty, IfcSimpleProperty, IfcComplexProperty

Use when you need to declare, read, or debug measured quantities on an IFC element : an IfcElementQuantity holding lengths, areas, volumes, counts, weights, times, and the IFC4.3 dimensionless number. Prevents putting a measured magnitude in a property set instead of a quantity set, a length unit on an area quantity that breaks the WR21 rule, a negative value that breaks WR22, attaching an IfcElementQuantity to a type with the wrong relationship, and using IfcQuantityNumber in a version that has no such entity. Covers IfcElementQuantity, IfcQuantitySet, IfcPhysicalQuantity, the seven IfcPhysicalSimpleQuantity subtypes, IfcPhysicalComplexQuantity, the Qto_ naming convention, attachment via IfcRelDefinesByProperties, and IFC2x3 / IFC4 / IFC4.3 version differences. Keywords: IFC quantities, IfcElementQuantity, IfcQuantitySet, IfcPhysicalQuantity, IfcPhysicalSimpleQuantity, IfcPhysicalComplexQuantity, IfcQuantityLength, IfcQuantityArea, IfcQuantityVolume, IfcQuantityCount, IfcQuantityWeight, IfcQuantityTime, IfcQ

Use when reading, writing, or debugging the .ifc STEP Physical File: the ISO-10303-21 skeleton, the HEADER section (FILE_DESCRIPTION, FILE_NAME, FILE_SCHEMA), the DATA section instance syntax, the special tokens, value notation, string escaping, or the ifcZIP container. Prevents emitting attributes out of declared order, serializing inverse or derived attributes, confusing the unset token with the derived token, writing raw non-ASCII bytes into a string, and putting more than one model file in an ifcZIP. Covers the file skeleton, the three header entities and the ViewDefinition convention, hash-id instance syntax, forward and backward references, dollar and asterisk tokens, enum and boolean dot notation, typed-value wrapping, aggregates, the control directives, and PKZip 2.04g ifcZIP packaging. Keywords: STEP physical file, SPF, .ifc, ISO 10303-21, Part 21, ISO-10303-21, HEADER, DATA, ENDSEC, FILE_DESCRIPTION, FILE_NAME, FILE_SCHEMA, ViewDefinition, positional attributes, dollar sign, asterisk, forward refere

Use when you need to declare, read, or debug the units of an IFC model : the project unit assignment, SI units with a prefix (millimetre = METRE + MILLI), imperial units via a conversion factor, compound units like velocity, monetary currency, and how a property value resolves to a concrete unit. Prevents a model that is off by 1000x because millimetres were declared as metres, a duplicate unit type that breaks the WR01 rule, inventing a separate "millimetre" unit name, and embedding a currency string in a numeric value. Covers IfcUnitAssignment, IfcSIUnit, IfcConversionBasedUnit and the WithOffset subtype, IfcDerivedUnit with IfcDerivedUnitElement, IfcContextDependentUnit, IfcMonetaryUnit, IfcMeasureWithUnit, the unit-propagation chain, and IFC2x3 / IFC4 / IFC4.3 version differences. Keywords: IFC units, IfcUnitAssignment, IfcSIUnit, IfcSIPrefix, IfcSIUnitName, IfcConversionBasedUnit, IfcDerivedUnit, IfcDerivedUnitElement, IfcContextDependentUnit, IfcMonetaryUnit, IfcMeasureWithUnit, IfcUnitEnum, IfcDerivedU

Use when asked about IFC5, the next generation of IFC, why IFC5 drops STEP, the composition or layering model, multi-author non-destructive editing, the .ifcx JSON format, or how IFC5 differs from IFC4.3. Prevents teaching IFC5 as a stable production target, inventing IFC5 entity or attribute names, confusing IFC5 the standard with IFCx the format, claiming IFC5 uses EXPRESS or STEP, and assuming the IFC4.3 objectified relationship pattern carries over. Covers the IN DEVELOPMENT status, the tree-based composition model, prim-style inheritance, multi-author layering, space boundaries as objects, TypeSpec as the schema language, external bSDD references, and what problem IFC5 solves versus IFC4.3. Keywords: IFC5, IFC 5, ifcx, .ifcx, composition, layering, multi-author, non-destructive editing, TypeSpec, tsp, prim, inheritance, JSON schema, ifcx.dev, bSDD, next-generation IFC, is IFC5 ready, can I use IFC5 in production, why does IFC5 drop STEP, what is the difference between IFC5 and IFC4, how does IFC5 work, I