Use Ifclite

Using ifc-lite

ifc-lite is a headless BIM toolkit for IFC files. It was built for LLM terminals: every command takes --json, stdout is data, stderr is status, and exit 0/1 means pass/fail. Prefer it over hand-parsing IFC text.

Start here (every session)

ifc-lite --help            # all commands
ifc-lite schema            # full SDK API as JSON (namespaces, methods, params) — read before writing eval/run code
ifc-lite info model.ifc --json   # schema version, entity counts, storeys, top types

If ifc-lite isn't installed, run via npx @ifc-lite/cli <command> or install with npm install -g @ifc-lite/cli.

Core workflows

# Query entities (use exact IFC type names; comma-separated for multiple)
ifc-lite query model.ifc --type IfcWall --json
ifc-lite query model.ifc --type IfcWall --where "Pset_WallCommon.IsExternal=true" --json
ifc-lite query model.ifc --type IfcWall --all --json    # props, quantities, materials, classifications, relationships
ifc-lite query model.ifc --type IfcDoor --count

# Inspect one entity fully
ifc-lite props model.ifc --id 42

# Export
ifc-lite export model.ifc --format csv --type IfcWall --columns Name,GlobalId,Pset_WallCommon.FireRating --out walls.csv
ifc-lite export model.ifc --format ifc --schema IFC4 --out filtered.ifc

# Validate against IDS rules (exit 1 on failure)
ifc-lite ids model.ifc requirements.ids --json

# Create IFC from scratch (30+ element types)
ifc-lite create wall --start 0,0,0 --end 5,0,0 --height 3 --thickness 0.2 --out wall.ifc

# Combine / convert / compare
ifc-lite merge arch.ifc struct.ifc mep.ifc --out federated.ifc
ifc-lite convert model.ifc --schema IFC4 --out v4.ifc
ifc-lite diff v1.ifc v2.ifc --by-entity --json

# Structural sanity check
ifc-lite validate model.ifc --json

The power tools: eval and run

When no flag fits, drop into the full SDK. The bim object is the entire @ifc-lite/sdk surface (discover it with ifc-lite schema).

ifc-lite eval model.ifc "bim.query().byType('IfcWall').count()"
ifc-lite eval model.ifc "bim.storeys().map(s => s.name)"
ifc-lite run analysis.js model.ifc           # a .js file with `bim` available globally

ifc-lite ask model.ifc "how many walls?" maps plain-English questions to common recipes — handy for quick one-offs, but eval is more precise.

For the complete command + flag reference (every command, all flags, the 30+ create element types, bsdd, clash, lod, view/analyze), read cli-reference.md.

Rules that keep IFC output correct

These are non-negotiable when emitting IFC names or editing models:

• Exact IFC EXPRESS names, never aliases. Types like IfcWallStandardCase, relationships like IfcRelAggregates (not Aggregates). Attributes in IFC PascalCase: GlobalId, Name, Description, ObjectType.
• STEP type names are stored UPPERCASE. Don't hand-case them — query results already carry the resolved IFC type in EntityData.type (e.g. entity.type === 'IfcWall'), so read that instead of reconstructing it.
• Single vs federated models are both first-class. When multiple files are merged/federated, IDs are namespaced; resolve through the federation registry rather than assuming globalId === expressId. (Single-model fallback: they're equal.)
• --where filters use PsetName.PropName=Value (e.g. Pset_WallCommon.IsExternal=true).
• Coordinates are IFC Z-up [x, y, z] when creating elements.

Tips for agent use

1. Always pass --json; pipe to jq for filtering.
2. Run ifc-lite schema before writing eval/run code.
3. Use --count for quick counts; --all to get full entity data in one call.
4. Use create --from-json (reads stdin) for programmatic generation.
5. Don't loop calling per-entity extraction; fetch in bulk with query --all.

Running as an MCP server (tool-calling agents)

For agents that speak the Model Context Protocol, @ifc-lite/mcp exposes the same capabilities as ~70 typed tools (model/query/IDS/BCF/clash/export/viewer/ mutation) plus pre-baked prompts.

ifc-lite mcp ./model.ifc                 # stdio transport (default)
ifc-lite mcp ./model.ifc --read-only     # hide all mutation tools
ifc-lite mcp ./arch.ifc ./struct.ifc --federate
ifc-lite mcp --transport http --port 8765 --token <secret>
# (equivalent standalone binary: ifc-lite-mcp …)

Tool families and the discovery-first calling pattern are documented in mcp-tools.md.