IfcSplitter

Splits large IFC files into smaller valid IFC files, or extracts a set of building elements into a new one, streaming the input so the whole file never has to be held as text in memory.

Each output file is a valid IFC containing its share of elements plus all shared infrastructure (spatial structure, geometry, materials, properties). Coupled elements (wall + opening + door, roof + slabs) are kept together.

File access goes through an IfcSplitterIO, so the same class works in Node.js, in the browser or against any other storage.

Constructors

new IfcSplitter()

new IfcSplitter(ifcSplitterIO, config): IfcSplitter

Parameters

Parameter	Type	Description
ifcSplitterIO	IfcSplitterIO	How to read the input file and write the output
files.
config	IfcSplitterConfig	Which IFC types to treat as elements and spatial structure,
and how to read relationship lists. Defaults apply to anything left out.

Returns

IfcSplitter

Properties

onExtractWarning

readonly onExtractWarning: Event <IfcSplitterWarningEvent>

Fires from extract when an id is missing or has a wrong type

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onProgress

readonly onProgress: Event <IfcSplitterProgressEvent>

Fires from split and extract each time a stage finishes, with the time it took.

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onSplitsResolved

readonly onSplitsResolved: Event <IfcSplitterGroupsEvent>

Fires from split once the content of every output file is resolved, just before the files are written.

Methods

extract()

extract(inputPath, elementIds, outputPath): Promise<Set<number>>

Extract specific building elements from an IFC file into a new IFC file.

Produces a single valid IFC containing only the requested elements and all of their dependencies (geometry, materials, styles, property sets). Void/fill coupling (wall + opening + door/window) and aggregation (roof + slabs, stair + flights) are automatically expanded so the output stays structurally consistent.

Parameters

Parameter	Type	Description
inputPath	string	Absolute or relative path to the source IFC file.
elementIds	number[]	Array of IFC entity IDs (#id) for the building elements to extract. Non-element or missing IDs are skipped, each reported through onExtractWarning.
outputPath	string	Path for the output IFC file.

Returns

Promise<Set<number>>

the IFC ids written to the output file.

Throws

if none of elementIds resolves to a building element. No output file is produced in that case.

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forEachLine()

forEachLine(filePath, callback): Promise<void>

Chunked file reader — replaces readline (3-5x faster)

Parameters

Parameter	Type	Description
filePath	string	Path of the file, read through the IfcSplitterIO.
callback	(line) => void | Promise<void>	Called with each line, awaited before the next one.

Returns

Promise<void>

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parseIfc()

parseIfc(filePath): Promise<ParseResult>

Reads an IFC file into its header lines, footer lines and an index of every data line by id. This is the first stage of split and extract.

Parameters

Parameter	Type	Description
filePath	string	Path of the IFC file, read through the IfcSplitterIO.

Returns

Promise<ParseResult>

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split()

split(inputPath, numGroups, outputPath): Promise<Map<number, object>>

Split an IFC file into N roughly equal groups of building elements.

Each output file is a valid IFC containing its share of elements plus all shared infrastructure (spatial structure, geometry, materials, properties). Coupled elements (wall + opening + door, roof + slabs) are kept together.

Parameters

Parameter	Type	Description
inputPath	string	Absolute or relative path to the source IFC file.
numGroups	number	Number of output files to produce. Not capped by the
splitter, but note that the write pass holds one open writer per non-empty
group, so the practical ceiling is the process' file descriptor limit.
outputPath	(groupId) => string	Given groupId returns output file path.

Returns

Promise<Map<number, object>>

a map keyed by GroupData.groupId with the path of each written file and the IFC ids it contains. Empty groups have no entry.

Throws

if numGroups is not a positive integer.