Data Flow¶
Detailed data flow through the IFClite system.
Complete Data Flow¶
flowchart TB
subgraph Input["Input"]
File["IFC File"]
URL["URL"]
Buffer["ArrayBuffer"]
end
subgraph Parse["Parse Stage"]
Scan["Scan Entities (memchr)"]
Build["Build Entity Index"]
Decode["Decode Attributes (lazy)"]
end
subgraph Store["Storage Stage"]
Entities["Entity Table"]
Properties["Property Table"]
Quantities["Quantity Table"]
Relations["Relationship Graph"]
end
subgraph Geometry["Geometry Stage"]
Extract["Extract Geometry"]
Triangulate["Triangulate"]
Transform["Transform"]
Buffer2["Build Buffers"]
end
subgraph Render["Render Stage"]
Upload["GPU Upload"]
Cull["Frustum Cull"]
Draw["Draw"]
Display["Display"]
end
Input --> Parse
Parse --> Store
Store --> Geometry
Geometry --> Render
style Input fill:#6366f1,stroke:#312e81,color:#fff
style Parse fill:#2563eb,stroke:#1e3a8a,color:#fff
style Store fill:#10b981,stroke:#064e3b,color:#fff
style Geometry fill:#f59e0b,stroke:#7c2d12,color:#fff
style Render fill:#a855f7,stroke:#581c87,color:#fff
Parsing Data Flow¶
Token Flow¶
Tokenization happens lazily, per entity, when attributes are decoded (the scan itself never builds tokens):
flowchart LR
subgraph Input["Input"]
Bytes["Entity byte span"]
end
subgraph Lexer["nom Tokenizer"]
WS["Skip Whitespace"]
Match["Match Token"]
Emit["Emit Token"]
end
subgraph Tokens["Token Types"]
EntityRef["EntityRef #123"]
String["String (borrowed bytes)"]
Number["Integer / Float"]
Enum["Enum .T./.F./..."]
List["List / TypedValue"]
end
Bytes --> WS --> Match --> Emit --> Tokens
Entity Parsing¶
sequenceDiagram
participant Input as Input Buffer
participant Scanner as Entity Scanner
participant Index as Entity Index
participant Decoder as Attribute Decoder
Input->>Scanner: Scan for #123=
Scanner->>Scanner: Extract type name
Scanner->>Index: Store (id, offset, type)
Note over Index: Lazy storage
Index->>Decoder: Request entity #123
Decoder->>Input: Read from offset
Decoder->>Decoder: Parse attributes
Decoder-->>Index: Return decoded entity
Memory Layout¶
graph TB
subgraph File["File Buffer (ArrayBuffer)"]
Header["HEADER Section"]
Data["DATA Section"]
End["END-ISO..."]
end
subgraph Index["Entity Index"]
I1["#1 → offset 1234, IFCPROJECT"]
I2["#2 → offset 2345, IFCSITE"]
I3["#3 → offset 3456, IFCWALL"]
end
Data --> I1
Data --> I2
Data --> I3
Storage Data Flow¶
Columnar Tables¶
flowchart LR
subgraph Decoded["Decoded Entities"]
E1["Entity 1"]
E2["Entity 2"]
E3["Entity 3"]
end
subgraph Columns["Columnar Storage"]
IDs["expressIds: Uint32Array<br/>[1, 2, 3, ...]"]
Types["typeEnums: Uint16Array<br/>[5, 12, 8, ...]"]
Names["nameIndices: Uint32Array<br/>[42, 0, 15, ...]"]
Flags["flags: Uint8Array<br/>[3, 1, 3, ...]"]
end
subgraph Strings["String Table"]
S1["'Project Name'"]
S2["'Wall-001'"]
S3["..."]
end
E1 --> IDs
E2 --> IDs
E3 --> IDs
Names --> Strings
Relationship Graph¶
graph LR
subgraph CSR["CSR Format"]
Offsets["offsets: [0, 2, 5, 7, ...]"]
Edges["edges: [2, 3, 4, 5, 6, 7, 8, ...]"]
Types["types: [1, 1, 2, 2, 2, 3, 3, ...]"]
end
subgraph Query["Query: Get children of #1"]
Start["offsets[1] = 0"]
End["offsets[2] = 2"]
Children["edges[0..2] = [2, 3]"]
end
Offsets --> Start
Offsets --> End
Edges --> Children
Geometry Data Flow¶
Processing Pipeline¶
flowchart TB
subgraph Extract["1. Extract"]
Entity["IFC Entity"]
Shape["Shape Representation"]
Placement["Local Placement"]
end
subgraph Route["2. Route"]
Router["GeometryRouter"]
ExtProc["Extrusion / Swept"]
BrepProc["Brep / AdvancedBrep"]
BoolProc["Boolean (exact CSG)"]
TessProc["Tessellated / Surface"]
MapProc["MappedItem (instancing)"]
end
subgraph Triangulate["3. Triangulate"]
Profile["Profile → 2D Points"]
Earcut["Earcut Triangulation"]
Normals["Compute Normals"]
end
subgraph Output["4. Output"]
Positions["Float32Array positions<br/>(relative to per-element origin)"]
NormalsOut["Float32Array normals"]
Indices["Uint32Array indices"]
Origin["origin: [f64; 3]"]
end
Extract --> Route
Route --> Triangulate
Triangulate --> Output
Coordinate Transformation¶
flowchart LR
subgraph Local["Local Coordinates"]
LP["Profile Points<br/>(2D, f64)"]
end
subgraph Transform["Transformations (f64)"]
Extrude["Extrude to 3D"]
Place["Apply Placement"]
RTC["Subtract RTC offset<br/>(large-coordinate models)"]
Frame["Split into per-element<br/>origin + local positions"]
end
subgraph GPU["GPU Coordinates"]
WP["Local Points (f32)<br/>+ origin [f64; 3]"]
end
LP --> Extrude --> Place --> RTC --> Frame --> WP
All placement math runs in f64 on the CPU; only the final per-element local positions are stored as f32, with the world-magnitude translation kept in the f64 origin. See Coordinate Handling.
Render Data Flow¶
Buffer Upload¶
flowchart TB
subgraph CPU["CPU Memory"]
Mesh["Mesh Data"]
Positions["positions: Float32Array"]
Normals["normals: Float32Array"]
Indices["indices: Uint32Array"]
end
subgraph Transfer["Transfer"]
Interleave["Interleave<br/>(pos + normal + entityId)"]
Write["queue.writeBuffer"]
end
subgraph GPU["GPU Memory"]
VBO["Vertex Buffer"]
IBO["Index Buffer"]
UBO["Uniform Buffer"]
end
CPU --> Transfer --> GPU
Render Pass¶
flowchart TB
subgraph Setup["Setup"]
Pass["Begin Render Pass"]
Pipeline["Set Pipeline"]
Bind["Bind Groups"]
end
subgraph Draw["Draw Loop"]
ForEach["For Each Batch / Instanced Shard"]
Cull["Frustum Cull (AABB)"]
SetBuffers["Set Buffers"]
DrawCall["Draw Indexed (+ instanced)"]
end
subgraph Finish["Finish"]
End["End Pass"]
Submit["Submit Commands"]
Present["Present Frame"]
end
Setup --> Draw --> Finish
Frame Timeline¶
gantt
title Frame Timeline (16.67ms @ 60fps)
dateFormat X
axisFormat %L ms
section CPU
Update Camera :a1, 0, 1
Frustum Cull :a2, 1, 2
Update Uniforms :a3, 2, 3
Build Commands :a4, 3, 5
section GPU
Vertex Shader :b1, 5, 8
Rasterization :b2, 8, 12
Fragment Shader :b3, 12, 15
Present :b4, 15, 17
Query Data Flow¶
Fluent Query¶
flowchart LR
subgraph Build["Build Query"]
Start["query"]
Type[".walls()"]
Filter[".whereProperty()"]
Select[".select()"]
end
subgraph Execute["Execute"]
Plan["Query Plan"]
Scan["Column Scan"]
Filter2["Apply Filters"]
Project["Project Fields"]
end
subgraph Result["Result"]
Array["Entity[]"]
end
Build --> Execute --> Result
SQL Query¶
flowchart TB
subgraph Input["Input"]
SQL["SQL Query String"]
end
subgraph DuckDB["DuckDB-WASM"]
Parse["Parse SQL"]
Optimize["Optimize Plan"]
Execute["Execute"]
end
subgraph Data["Data Sources"]
Entities["entities table"]
Properties["properties table"]
Quantities["quantities table"]
end
subgraph Output["Output"]
Rows["Result Rows"]
end
SQL --> DuckDB
Data --> DuckDB
DuckDB --> Rows
Export Data Flow¶
Exporters are implemented in Rust (rust/export: glTF/GLB, STEP/IFC, IFC5/IFCX, CSV, JSON, OBJ, KMZ, HBJSON, Parquet, and more) and surfaced through the WASM API and the CLI. The TypeScript @ifc-lite/export package hosts the browser-side orchestration (merged export, schema conversion, change sets).
glTF Export¶
flowchart TB
subgraph Input["Input"]
ParseResult["ParseResult"]
Meshes["Mesh Data"]
Props["Properties"]
end
subgraph Convert["Conversion"]
Nodes["Build Node Tree"]
Buffers["Pack Buffers"]
Materials["Export Materials"]
Extras["Add Extras (props)"]
end
subgraph Output["Output"]
JSON[".gltf JSON"]
BIN[".bin Binary"]
GLB[".glb (combined)"]
end
Input --> Convert
Convert --> Output
Data Size Estimates¶
| Stage | Data Size (50MB IFC) | Notes |
|---|---|---|
| File Buffer | 50 MB | Original file |
| Entity Index | ~2 MB | Just offsets + types |
| Columnar Tables | ~5 MB | Deduped, compact |
| Relationship Graph | ~1 MB | CSR format |
| Geometry Buffers | ~20 MB | Triangulated meshes |
| GPU Buffers | ~20 MB | Mirrors CPU |
Multi-Model Federation Data Flow¶
When multiple IFC files are loaded, each model is assigned a unique ID offset by the FederationRegistry:
flowchart TB
subgraph Files["Input Files"]
File1["Model A.ifc"]
File2["Model B.ifc"]
end
subgraph Registry["FederationRegistry"]
Reg1["Model A: offset=0, max=5000"]
Reg2["Model B: offset=5000, max=3000"]
end
subgraph Store["Zustand Store"]
Models["models Map<br/>FederatedModel[]"]
Selection["selectionSlice<br/>EntityRef: modelId + expressId"]
Visibility["visibilitySlice<br/>globalIds in hiddenEntities"]
end
Files --> Registry
Registry --> Store
Click["User Click"] --> GlobalId["globalId from GPU"]
GlobalId --> Resolve["resolveGlobalIdFromModels"]
Resolve --> EntityRef["{ modelId, expressId }"]
EntityRef --> Selection
All mesh geometry uses global IDs (expressId + offset) for the GPU pick buffer, while the application logic uses EntityRef ({ modelId, expressId }) for unambiguous references.
Mutation Data Flow¶
Property editing flows through the MutablePropertyView overlay:
flowchart LR
subgraph Read["Read Path"]
Query["Get Property"] --> Check["Check Overlay"]
Check -->|Has Override| Overlay["Return Mutated Value"]
Check -->|No Override| Original["Return Original Value"]
end
subgraph Write["Write Path"]
Edit["Set Property"] --> Record["Record Mutation<br/>(old + new value)"]
Record --> UpdateOverlay["Update Overlay Map"]
Record --> UndoStack["Push to Undo Stack"]
end
subgraph Export["Export"]
Changes["All Mutations"] --> ChangeSet["Change Set JSON"]
Changes --> IFCExport["Modified IFC File"]
end
Next Steps¶
- Parsing Pipeline - Parser details
- Geometry Pipeline - Geometry details
- Rendering Pipeline - Renderer details
- Federation Architecture - Multi-model federation details