Sverchok Impl Ifcsverchok

sverchok-impl-ifcsverchok

Quick Reference

What Is IfcSverchok

IfcSverchok is an extension that bridges Sverchok parametric geometry with the IFC (Industry Foundation Classes) open BIM standard. It enables creation of native IFC models using visual node-based programming in Blender.

• 31 specialized nodes (24 IFC + 7 Shape Builder) for BIM model creation
• Two geometry modes: Blender mesh objects or raw Sverchok geometry to IFC
• Transient IFC file: single shared SvIfcStore.file managed across all nodes
• Bonsai integration: toggle to read/write Bonsai's active IFC file
• Status: Alpha (version 0.0.0) — expect stability issues

Dependency Chain

IfcSverchok
  ├── Bonsai (BlenderBIM) — must be enabled first
  ├── Sverchok v1.2+ — node tree framework
  └── ifcopenshell 0.8.x — IFC file manipulation

All three dependencies must be installed and enabled. IfcSverchok registers its nodes only when all dependencies are available.

Critical Warnings

NEVER use Blender undo inside an IfcSverchok node tree — this causes crashes due to the transient SvIfcStore.file becoming out of sync with Blender's undo state.

NEVER assume multiple IFC files can coexist — SvIfcStore manages exactly ONE transient file shared by ALL nodes in ALL trees. Running "Re-run all nodes" calls purge() which resets the entire file.

NEVER mix use_bonsai_file=True with SvIfcWriteFile export — writing overwrites Bonsai's active file state. Use one mode or the other.

NEVER expect IfcSverchok's process() to follow standard Sverchok conventions — SvIfcCore applies zip_long_repeat TWICE (double-nested), which is different from regular Sverchok nodes that apply it once.

ALWAYS include a geometry-to-representation conversion node (SvIfcBMeshToIfcRepr or SvIfcSverchokToIfcRepr) before SvIfcCreateEntity — entities without representations produce empty IFC files.

ALWAYS let ensure_hirarchy() handle missing spatial structure on export rather than manually creating IfcProject/IfcSite/IfcBuilding — the write node auto-completes the hierarchy.

Decision Tree

Need to create IFC from Sverchok geometry?
├── From Blender mesh objects → SvIfcBMeshToIfcRepr node
├── From Sverchok vertices/faces → SvIfcSverchokToIfcRepr node
├── From IFC ShapeBuilder profiles → SvIfcSbRectangle → SvIfcSbExtrude → SvIfcSbRepresentation
└── From existing IFC file → SvIfcReadFile node

Need to build IFC hierarchy?
├── Quick setup → SvIfcQuickProjectSetup (creates project + site + building + storey)
├── Manual hierarchy → SvIfcAddSpatialElement for each level
└── Minimal → Just use SvIfcCreateEntity + SvIfcWriteFile (ensure_hirarchy fills gaps)

Need to query IFC data?
├── By STEP ID → SvIfcById node
├── By GlobalId → SvIfcByGuid node
├── By IFC class → SvIfcByType node
├── By selector query → SvIfcByQuery node
└── Read attributes → SvIfcReadEntity node

Need Bonsai integration?
├── Write to Bonsai's file → Toggle "Use Bonsai File" button, then run nodes
├── Read Bonsai's file → Toggle "Use Bonsai File", use query nodes
└── Export standalone → Keep use_bonsai_file=False (default), use SvIfcWriteFile

Essential Patterns

Pattern 1: SvIfcStore: Transient File Management

# IfcOpenShell 0.8.x / IfcSverchok
# SvIfcStore manages a SINGLE transient IFC file across the node tree.

class SvIfcStore:
    file: Union[ifcopenshell.file, None] = None
    id_map: dict[str, Any] = {}        # node_id -> created entity data
    schema_identifiers = ["IFC4", "IFC2X3"]
    use_bonsai_file = False

    @staticmethod
    def purge() -> None:
        """Reset all state. Called before each full node tree re-run."""
        SvIfcStore.file = None
        SvIfcStore.id_map = {}

    @staticmethod
    def get_file() -> ifcopenshell.file:
        """Return the current transient file.
        Creates boilerplate IFC4 file if none exists.
        Returns Bonsai's file when use_bonsai_file is True."""
        if SvIfcStore.use_bonsai_file:
            return tool.Ifc.get()
        if SvIfcStore.file is None:
            SvIfcStore.create_boilerplate()
        return SvIfcStore.file

Key behaviors:

• purge() runs at the start of every full tree re-evaluation
• id_map tracks which node created which IFC entities (keyed by node_id)
• get_file() lazily creates a boilerplate IFC4 file on first access
• Only ONE file exists at a time — no multi-file workflows

Pattern 2: SvIfcCore: Double-Nested Input Processing

# IfcOpenShell 0.8.x / IfcSverchok
# SvIfcCore applies zip_long_repeat TWICE: different from standard Sverchok.

from sverchok.data_structure import zip_long_repeat

class SvIfcCore:
    sv_input_names: list[str]

    def process(self) -> None:
        # Gather all inputs
        sv_inputs_nested = []
        for name in self.sv_input_names:
            sv_inputs_nested.append(self.inputs[name].sv_get())

        # FIRST zip_long_repeat: across objects (outer nesting level)
        for sv_input_nested in zip_long_repeat(*sv_inputs_nested):
            # SECOND zip_long_repeat: within each object (inner nesting level)
            for sv_input in zip_long_repeat(*sv_input_nested):
                sv_input = list(sv_input)
                self.process_ifc(*sv_input)

Why double-nested: Sverchok data is [[obj1_data], [obj2_data]]. The first zip matches across inputs at the object level. The second zip iterates within each object, processing individual items. This allows a single SvIfcCreateEntity node to create multiple entities across multiple objects.

Pattern 3: Sverchok Geometry to IFC Representation

# IfcOpenShell 0.8.x / IfcSverchok
# Converting Sverchok geometry (vertices, edges, faces) to IFC representation.
# Node: SvIfcSverchokToIfcRepr

# In a Sverchok node tree, connect:
# [Plane Generator] → Vertices → [SvIfcSverchokToIfcRepr] → Representation → [SvIfcCreateEntity]
#                   → Faces    → /

# SvIfcSverchokToIfcRepr internally:
# 1. Normalizes vertex/edge/face data to 4-deep nesting
# 2. Zips geometry objects together
# 3. For each geometry object:
#    - Creates IfcCartesianPointList3D from vertices
#    - Creates IfcTriangulatedFaceSet or IfcPolygonalFaceSet from faces
#    - Wraps in IfcShapeRepresentation with context_type/context_identifier
# 4. Outputs IFC representation entity IDs

Pattern 4: Blender Mesh to IFC Representation

# IfcOpenShell 0.8.x / IfcSverchok
# Converting Blender mesh objects to IFC representations.
# Node: SvIfcBMeshToIfcRepr

# In a Sverchok node tree, connect:
# [Objects In] → Objects → [SvIfcBMeshToIfcRepr] → Representations → [SvIfcCreateEntity]
#                                                 → Locations      → /

# SvIfcBMeshToIfcRepr internally:
# 1. Takes Blender mesh objects as input
# 2. Separates loose parts into individual geometry sets
# 3. Generates IFC representation per object
# 4. Preserves world matrices as Locations output
# 5. Outputs: Representations (IFC repr IDs) + Locations (4x4 matrices)

# Inputs:
#   context_type: "Model" or "Plan"
#   context_identifier: "Body", "Annotation", "Box", or "Axis"
#   target_view: geometric target view
#   blender_objects: list of Blender mesh objects

Pattern 5: 6-Step IFC Generation Workflow

# IfcOpenShell 0.8.x / IfcSverchok
# Complete workflow for generating a valid IFC file from Sverchok.

# Step 1: Generate Geometry
# Use any Sverchok generator nodes (Box, Plane, Cylinder, etc.)
# OR use ShapeBuilder nodes (SvIfcSbRectangle → SvIfcSbExtrude)
# OR use Blender Objects In node

# Step 2: Convert to IFC Representation
# [SvIfcSverchokToIfcRepr]: from Sverchok vertices/edges/faces
# [SvIfcBMeshToIfcRepr]   : from Blender mesh objects
# [SvIfcSbRepresentation] : from ShapeBuilder geometry

# Step 3: Create IFC Entities
# [SvIfcCreateEntity]
#   IfcClass = "IfcWall"  (or IfcSlab, IfcColumn, etc.)
#   Names = "Wall_001"
#   Representation = (from Step 2)

# Step 4: Build Spatial Hierarchy
# [SvIfcAddSpatialElement]
#   IfcClass = "IfcBuildingStorey"
#   Elements = (from Step 3)
# Or skip: ensure_hirarchy() auto-completes on export

# Step 5: Add Properties (Optional)
# [SvIfcAddPset]
#   Name = "Pset_WallCommon"
#   Properties = '{"IsExternal": true, "LoadBearing": false}'

# Step 6: Export
# [SvIfcWriteFile]
#   path = "/path/to/output.ifc"
#   Triggers ensure_hirarchy() automatically

Pattern 6: ShapeBuilder Workflow

# IfcOpenShell 0.8.x / IfcSverchok
# Using ShapeBuilder nodes to create IFC geometry natively.

# ShapeBuilder creates geometry directly as IFC entities,
# bypassing Blender/Sverchok mesh conversion entirely.

# Node chain:
# [SvIfcSbRectangle] → profile → [SvIfcSbExtrude] → shape → [SvIfcSbRepresentation] → repr
#   XDim = 0.3                     Magnitude = 3.0
#   YDim = 0.2

# SvIfcSbRectangle creates an IfcRectangleProfileDef
# SvIfcSbExtrude extrudes the profile into an IfcExtrudedAreaSolid
# SvIfcSbRepresentation wraps into IfcShapeRepresentation

# Available ShapeBuilder nodes:
# SvIfcSbRectangle: rectangle profile
# SvIfcSbExtrude  : extrusion along axis
# SvIfcSbRepresentation: wraps to shape representation
# SvSbMesh        : creates IFC mesh from vertices/polygons
# SvSbPolyline    : creates IFC polyline from vertices
# SvSbShapeOutput : converts IFC shape back to Sverchok geometry
# SvIfcSbTest     : debug/testing node

Pattern 7: Automatic Hierarchy Completion (ensure_hirarchy)

# IfcOpenShell 0.8.x / IfcSverchok
# Called automatically by SvIfcWriteFile before export.

# ensure_hirarchy() performs these steps:
# 1. Creates a default IfcBuilding if none exists in the file
# 2. Assigns orphaned IfcBuildingStorey elements to the building
# 3. Assigns uncontained IfcElement instances to the building
# 4. Creates a default IfcSite if none exists
# 5. Links Building → Site → Project

# This means a minimal workflow can skip manual hierarchy:
# [Geometry] → [Repr] → [CreateEntity] → [WriteFile]
# ensure_hirarchy() fills in Project/Site/Building automatically.

# NOTE: The function is named "ensure_hirarchy" (typo preserved from source).
# Do NOT attempt to call "ensure_hierarchy": the correct name has no second 'e'.

Common Operations

Complete Node Catalog (31 Nodes)

IFC Nodes (24)

IFC Shape Builder Nodes (7)

SvIfcStore Static Methods

SvIfcStore Class Attributes

Geometry Mode Comparison

Known Issues and Limitations

Reference Links

• references/methods.md — Complete API signatures for SvIfcStore, SvIfcCore, all 31 nodes, and ensure_hirarchy
• references/examples.md — Working code examples for IFC generation workflows, ShapeBuilder, Bonsai integration
• references/anti-patterns.md — What NOT to do with IfcSverchok, with explanations

Cross-References

• ifcos-core-concepts — IfcOpenShell fundamentals
• ifcos-syntax-elements — IFC element types and attributes
• ifcos-impl-creation — Creating IFC entities with ifcopenshell.api
• bonsai-core-architecture — Bonsai addon architecture

Official Sources

• https://github.com/IfcOpenShell/IfcOpenShell/tree/v0.8.0/src/ifcsverchok
• https://community.osarch.org/discussion/284/sverchok-ifc