Public API

The RvtIO package is the supported surface listed here. Everything else (parsers, geometry carriers, schema classes, census types, the stream decoders) is internal; it can change in any release and is visible only to the test and tool projects through InternalsVisibleTo.

Reading a file

Type	Use
RvtDocument	Opens a file (Open) and gives the elements, project information, file metadata and category lookups.
RvtFileReader	Lower level read (Read) that returns the RevitFileInfo behind a document.
RvtReaderOptions	Options of a read, including DiagnosticOutput, ResolveCurrentCopies (keeps only the current copy of an element that several partition streams hold; default true, set it to false to decode every copy), RaiseLimits and Diagnostics. RevitLocalizationDirectory is [Obsolete] and ignored: the texts are built in.
RvtReadDiagnostics, StreamRecord, ReaderLimitHit	What a read collects when RvtReaderOptions.Diagnostics is set: the partition streams read and the streams cut by a limit.
ExportReport, SkipLog	The machine-readable report of a run (ToJson) and the elements an export left out; see the export report.
RvtExitCodes, RvtInputException, RvtLimitException, RvtContainerCheck	The exit codes 0 to 4 and 6 of the command line tool (code 5 is returned only by downgrade --check), the exceptions RvtFileReader.Read throws for a file it cannot read, and the check that raises them.
FilteredElementCollector	Query over the elements of a document (OfCategory, WhereElementIsNotElementType, Where, ...).

Model

Element, Parameter, Definition, ParameterDefinition, StorageType, RevitFileInfo, FileMetadata, ProjectInfo, TransmissionInfo, ExternalFileRef, ClassSchema, ClassField, MaterialLayer and the geometry types (GeometryData, GeoFace, GeoEdge, GeoSolid, GeoBrepSolid, GeoOpening, GeoInstance, LocationCurve, DimensionData, InstanceTransform) are the data a read returns. ParameterListConverter is the System.Text.Json converter that writes the parameter lists of a RevitFileInfo.

Element.BoundingBox is the axis-aligned outline stored in the element header, as the Revit API bounding box (null for elements with no stored outline, such as grids and levels). The tight box of the decoded geometry is Element.Geometry.BoundingBox; before 0.3.0 Element.BoundingBox held that decoded value, which also changes the result of FilteredElementCollector.WhereBoundingBoxIsNotNull.

Built-in identifiers

BuiltInCategory, BuiltInParameter, BuiltInParameterGroup, ParameterType, UnitType, DisplayUnitType, UnitSymbolType, UnitGroup, MEPSystemClassification, FlowDirectionType, PipeFlowConfigurationType and their extension and label helpers carry the ids and names stored in the file format.

Export

Type	Use
IfcExporter	Writes IFC from a RevitFileInfo (Export). Properties: Profile, BaseQuantities, OpeningQuantitiesSwapped (true writes the legacy Width and Height of door and window openings; default false), OpeningQuantitiesInHostAxes (the opposite of it, kept for compatibility), ExportPhaseId, ExportAllPhases, RoomExportPhaseId, ExportRoomsOfAllPhases, RevitParameterGroups, SkipLog, ExportedProducts, DiagnosticOutput.
IfcProfile	Legacy or Current (the default) output profile.
IfcUnitFamily	The length unit family an export of the current profile declares, by the length format of the project: Metre for metres and for metres and centimetres, Foot for feet, feet and fractional inches and US survey feet, Millimetre for millimetres, for every other format and for an unreadable one. The legacy profile always declares millimetres.
CompactJsonExporter	Export(rvtPath, outputPath, readerOptions, options) reads a file and writes the compact JSON.
CompactJsonExportOptions	JsonClassNamePrefix: text put in front of every class name in the name field.

Triangle meshes

Type	Use
ElementMeshes	Extract(document, options) returns the triangle meshes of the drawable model elements of an opened RvtDocument, from the geometry the document already holds (the file is not read again). Coordinates are in feet, in the coordinates of the document (Revit internal coordinates, Z up).
ElementMeshOptions	UseSymbolPlacements (default true): an element that is exactly its family symbols placed rigidly is returned as placements of shared symbol meshes; false gives every element its own triangles.
MeshSet	Elements (one ElementMesh per drawable element, in document order), Symbols (symbol element id to its triangle meshes in the frame of the family, only for placed symbols) and GeometryUndecoded (a file of a release other than Revit 2022, read by its own class schema, opened without RvtReaderOptions.R22Layout: its elements are listed as Undecoded).
ElementMesh	ElementId, Meshes (the element's own triangles, one mesh per material), Placements, Coverage and UntriangulatedFaces.
TriangleMesh	Positions (x, y, z per vertex), Indices (three per triangle, counter-clockwise around the normals), Normals (one unit normal per vertex, flat per face: vertices are not shared between faces) and MaterialId (the material element id, 0 for none).
SymbolPlacement, MeshTransform, MeshVector	A symbol id with its transform. MeshTransform maps a family point p to Origin + BasisX * p.X + BasisY * p.Y + BasisZ * p.Z; the basis vectors are the columns of the row-major 3x3 matrix of GeoInstance.Transform (BasisX = (t[0], t[3], t[6]), Origin = (t[9], t[10], t[11]), see FromRowMajor). A negative Determinant is a mirror image.
MeshCoverage	Complete, Partial (some faces did not triangulate, a placed symbol or a symbol nested in one has no geometry, or a Geometry node that Revit exports has no decoded polygon), BoxSubstitute (a symbol placed at a rescaled placement was replaced by its box), NoGeometry (a geometry record with nothing to draw) and Undecoded.

A placement is given only when it is shown that the element is exactly its symbols placed: the element's geometry record holds no face of its own, the tight box of the element cut nothing off the placed symbols, every symbol resolved, no box was put in the place of a component, and every transform is rigid (orthonormal, determinant 1 or -1). Any other element, a cut or clipped instance included, gets its own triangles. The shared symbol triangles keep the winding of the family: a consumer that culls back faces reverses the winding of a placement with a negative determinant. The own triangles of an element, those of a mirrored instance included, are wound around the normals of their faces.

The drawable elements follow a subset of the product rules of the IFC export of the current profile, and the materials and the hidden Geometry nodes follow its rules: they are listed in the documentation comment of ElementMeshes, with the product rules that are not applied (the "export to IFC" flag, topography, walls that are not visible and others), so the meshes can include elements that the IFC leaves out. Curved surfaces are the dense polygons the reader decodes for them.

Diagnostics

The library never writes to the console. A diagnostic message is written only when the caller gives a TextWriter: RvtReaderOptions.DiagnosticOutput for a read (and for CompactJsonExporter.Export), IfcExporter.DiagnosticOutput (or the constructor argument) for an IFC export. The default is null, which is silent. The writer is scoped to the call that received it, so concurrent calls with different writers do not mix.

The rvtio command line tool sets the writer to standard error.