aec-agents-workflow-orchestrator

AEC Workflow Orchestrator

Scope: Multi-technology workflow orchestration for Blender + IfcOpenShell + Bonsai Version coverage: Blender 3.x-5.x | IfcOpenShell 0.8.x | IFC2X3/IFC4/IFC4X3 | Bonsai v0.8.x Role: Agent-level skill — routes tasks, sequences operations, coordinates technology boundaries

Critical Warnings

ALWAYS determine the execution context FIRST: standalone Python, Blender Python, or Bonsai-loaded. The available API surface differs per context.
NEVER mix IfcStore.get_file() (Bonsai) with ifcopenshell.open() on the same file. Bonsai owns the in-memory IFC graph.
ALWAYS use ifcopenshell.api.run() for IFC mutations in ALL contexts. NEVER modify entity attributes directly.
ALWAYS call bpy.ops.bim.edit_object_placement() after moving Blender objects when Bonsai is active.
NEVER use blenderbim.* imports. Use bonsai.* (renamed in v0.8.0, 2024).
ALWAYS set up units and geometric contexts before creating geometry.
NEVER use void.add_opening() in Bonsai v0.8.0+. Use feature.add_feature().

Quick Reference: Technology Selection Decision Tree

What does the task require?
|
+-- Pure IFC data manipulation (no 3D viewport needed)?
|   |
|   +-- Single file processing?
|   |   --> Standalone IfcOpenShell
|   |   --> Import: ifcopenshell, ifcopenshell.api
|   |   --> File: ifcopenshell.open(path) or project.create_file
|   |
|   +-- Batch processing multiple files?
|       --> Standalone IfcOpenShell in a loop
|       --> pathlib.Path.glob("*.ifc") iteration pattern
|       --> NO Blender dependency required
|
+-- IFC data + 3D visualization (view geometry in viewport)?
|   |
|   +-- Read-only visualization (no BIM editing)?
|   |   --> IfcOpenShell geometry extraction + Blender bpy
|   |   --> ifcopenshell.geom.create_shape() -> bpy mesh
|   |   --> Lightweight, no Bonsai dependency
|   |
|   +-- BIM authoring (create/edit IFC elements with visual feedback)?
|       --> Bonsai-loaded context (Blender + Bonsai addon)
|       --> IfcStore.get_file() for IFC access
|       --> bpy.ops.bim.* for operations with Blender sync
|
+-- Pure Blender 3D operations (no IFC/BIM)?
|   --> Standard Blender Python (bpy)
|   --> No IfcOpenShell or Bonsai needed
|   --> Refer to blender-core-api skill
|
+-- Parametric/generative design (arrays, patterns, data-driven geometry)?
|   |
|   +-- Visual node-based workflow?
|   |   --> Sverchok (SverchCustomTreeType node trees)
|   |   --> Refer to sverchok-core-concepts, sverchok-impl-parametric
|   |
|   +-- Generate IFC from parametric geometry?
|   |   --> IfcSverchok (31-node IFC bridge inside Sverchok)
|   |   --> Refer to sverchok-impl-ifcsverchok
|   |
|   +-- Building topology analysis (adjacency, envelope, dual graph)?
|       --> TopologicSverchok
|       --> Refer to sverchok-impl-topologic
|
+-- Headless automation (CI/CD, server, batch)?
    |
    +-- IFC-only operations?
    |   --> python script.py (standalone IfcOpenShell)
    |
    +-- Blender operations needed?
        --> blender --background --python script.py
        --> NEVER use viewport-dependent operators in background mode

Workflow Patterns

Pattern A: IFC-First Workflow

Use when: The primary deliverable is an IFC file. Blender is optional (for visualization only).

Step 1: Create/Open IFC (IfcOpenShell)
  --> ifcopenshell.api.run("project.create_file") or ifcopenshell.open()

Step 2: Build structure (IfcOpenShell)
  --> Create spatial hierarchy: Project -> Site -> Building -> Storey
  --> Set units and geometric contexts

Step 3: Create elements (IfcOpenShell)
  --> root.create_entity for each element
  --> geometry.add_*_representation for shapes
  --> spatial.assign_container for placement

Step 4: Enrich (IfcOpenShell)
  --> pset.add_pset + pset.edit_pset for properties
  --> type.assign_type for type assignments
  --> material.assign_material for materials

Step 5 (optional): Visualize (Blender)
  --> ifcopenshell.geom.create_shape() -> bpy mesh
  --> OR open in Bonsai for interactive inspection

Step 6: Export (IfcOpenShell)
  --> model.write("output.ifc")

Pattern B: Blender-First Workflow

Use when: Starting from Blender geometry that needs BIM data attached.

Step 1: Create geometry (Blender bpy)
  --> bpy.data.meshes.new() + mesh.from_pydata()
  --> OR use bpy.ops.mesh.primitive_*_add()
  --> OR import from external format (FBX, OBJ, glTF)

Step 2: Prepare for BIM (Blender)
  --> Organize into collections matching spatial hierarchy
  --> Name objects according to IFC conventions
  --> Clean geometry (manifold, correct normals)

Step 3: Assign IFC identity (Bonsai)
  --> Load Bonsai addon
  --> Create IFC project: bpy.ops.bim.create_project()
  --> Assign IFC classes to Blender objects
  --> bpy.ops.bim.assign_class() for each object

Step 4: Enrich (Bonsai + IfcOpenShell)
  --> Add property sets via ifcopenshell.api.run("pset.*")
  --> Assign types, materials, classifications
  --> Build spatial containment

Step 5: Save (Bonsai)
  --> model.write("output.ifc") via IfcStore

Pattern C: Bonsai-Native Workflow

Use when: Full BIM authoring with live IFC integration.

Step 1: Initialize project (Bonsai)
  --> bpy.ops.bim.create_project(schema="IFC4")
  --> Sets up IfcProject, default units, contexts automatically

Step 2: Build spatial structure (Bonsai)
  --> bpy.ops.bim.add_building() / bpy.ops.bim.add_storey()
  --> Spatial hierarchy managed by Bonsai operators

Step 3: Create BIM elements (Bonsai)
  --> bpy.ops.bim.add_wall() / add_slab() / add_column()
  --> Each operator creates IFC entity + Blender mesh simultaneously
  --> Bidirectional sync is automatic

Step 4: Edit properties (Bonsai + IfcOpenShell)
  --> model = IfcStore.get_file()
  --> ifcopenshell.api.run("pset.add_pset", model, ...)
  --> OR use Bonsai property panels

Step 5: Validate and save (Bonsai)
  --> Validate spatial containment, property completeness
  --> bpy.ops.bim.save_project() — writes .ifc directly

Multi-Step Orchestration: Common AEC Pipelines

Pipeline 1: IFC Creation + Validation + Visualization

[IfcOpenShell: Create]  -->  [IfcOpenShell: Validate]  -->  [Blender: Visualize]
                                                              (optional)
Technologies: IfcOpenShell (required), Blender (optional)
Execution: Standalone Python -> (optional) Blender Python

Sequencing rules:

Create the complete IFC model BEFORE validation
Validate BEFORE visualization (do not visualize broken models)
Visualization requires ifcopenshell.geom (compiled C++ extension)

Pipeline 2: Multi-File Property Enrichment

[IfcOpenShell: Open files]  -->  [IfcOpenShell: Read/Map]  -->  [IfcOpenShell: Enrich]  -->  [IfcOpenShell: Write]
Technologies: IfcOpenShell only
Execution: Standalone Python

Sequencing rules:

Open source files read-only; write to separate output directory
NEVER modify GlobalIds on existing entities
Preserve OwnerHistory on IFC2X3 files (MANDATORY)

Pipeline 3: Blender Model to IFC Export

[Blender: Geometry]  -->  [Bonsai: Assign IFC]  -->  [IfcOpenShell: Enrich]  -->  [Bonsai: Save]
Technologies: Blender (required), Bonsai (required), IfcOpenShell (required)
Execution: Blender Python with Bonsai addon loaded

Sequencing rules:

Geometry MUST be clean before IFC assignment (manifold, correct normals)
Assign IFC classes BEFORE adding properties
Create spatial hierarchy BEFORE assigning containers

Pipeline 4: IFC Analysis + Report Generation

[IfcOpenShell: Open]  -->  [IfcOpenShell: Query/Traverse]  -->  [Python: Generate Report]
Technologies: IfcOpenShell (required), standard Python (csv, json)
Execution: Standalone Python

Sequencing rules:

Use ifcopenshell.util.element.get_psets() for property extraction
Use model.by_type() for element enumeration
Handle schema differences: IFC2X3 vs IFC4 entity names

Pipeline 5: Bonsai Authoring + Standalone Post-Processing

[Bonsai: Author]  -->  [Save .ifc]  -->  [IfcOpenShell: Post-process]  -->  [Write .ifc]
Technologies: Bonsai (step 1), IfcOpenShell standalone (step 2)
Execution: Blender + Bonsai -> Standalone Python (separate process)

Sequencing rules:

Save from Bonsai FIRST, THEN open in standalone IfcOpenShell
NEVER have Bonsai and standalone IfcOpenShell open the same file simultaneously
Post-processing runs in a SEPARATE Python process (not inside Blender)

Technology Bridge Patterns

Bridge 1: IfcOpenShell -> Blender (Geometry Transfer)

# Convert IFC geometry to Blender mesh
# Context: Blender Python | Version: Blender 3.x-5.x, IfcOpenShell 0.8.x
import ifcopenshell
import ifcopenshell.geom
import bpy

ifc_file = ifcopenshell.open("model.ifc")
settings = ifcopenshell.geom.settings()
settings.set(settings.USE_WORLD_COORDS, True)

for element in ifc_file.by_type("IfcProduct"):
    if element.Representation is None:
        continue
    shape = ifcopenshell.geom.create_shape(settings, element)
    verts = shape.geometry.verts
    faces = shape.geometry.faces
    vertices = [(verts[i], verts[i+1], verts[i+2]) for i in range(0, len(verts), 3)]
    triangles = [(faces[i], faces[i+1], faces[i+2]) for i in range(0, len(faces), 3)]
    mesh = bpy.data.meshes.new(name=element.Name or element.is_a())
    mesh.from_pydata(vertices, [], triangles)
    mesh.update()
    obj = bpy.data.objects.new(element.Name or element.is_a(), mesh)
    bpy.context.collection.objects.link(obj)

Bridge 2: Blender -> IfcOpenShell (Geometry Export)

# Extract Blender mesh data for IFC representation
# Context: Blender Python | Version: Blender 3.x-5.x
import bpy
import ifcopenshell
import ifcopenshell.api

obj = bpy.context.active_object
depsgraph = bpy.context.evaluated_depsgraph_get()
obj_eval = obj.evaluated_get(depsgraph)
mesh = obj_eval.to_mesh()

verts = [tuple(v.co) for v in mesh.vertices]
faces = [tuple(p.vertices) for p in mesh.polygons]

obj_eval.to_mesh_clear()  # ALWAYS clean up evaluated mesh

# Create IFC representation from extracted data
# Use ifcopenshell.api for tessellated representation

Bridge 3: Bonsai <-> IfcOpenShell (Bidirectional Entity Access)

# Context: Blender with Bonsai loaded | Version: Bonsai v0.8.x
import bpy
from bonsai.bim.ifc import IfcStore
import ifcopenshell.util.element

model = IfcStore.get_file()
if model is None:
    raise RuntimeError("No IFC project loaded")

# Blender object -> IFC entity
obj = bpy.context.active_object
ifc_id = obj.BIMObjectProperties.ifc_definition_id
if ifc_id == 0:
    raise RuntimeError("Object is not linked to IFC")
entity = model.by_id(ifc_id)

# IFC entity -> Blender object (via IfcStore maps)
blender_obj = IfcStore.id_map.get(entity.id())

# Read properties from IFC entity
psets = ifcopenshell.util.element.get_psets(entity)
container = ifcopenshell.util.element.get_container(entity)
element_type = ifcopenshell.util.element.get_type(entity)

Bridge 4: Context Detection (Runtime Environment Probe)

# Detect available technologies at runtime
def detect_context():
    """Determine which AEC technologies are available."""
    context = {"blender": False, "bonsai": False, "ifcopenshell": False}

    try:
        import bpy
        context["blender"] = True
        context["blender_version"] = bpy.app.version
    except ImportError:
        pass

    try:
        import ifcopenshell
        context["ifcopenshell"] = True
    except ImportError:
        pass

    if context["blender"]:
        try:
            from bonsai.bim.ifc import IfcStore
            context["bonsai"] = True
            context["bonsai_has_file"] = IfcStore.get_file() is not None
        except ImportError:
            pass

    return context

Execution Context Compatibility Matrix

Operation	Standalone Python	Blender Python	Bonsai Context
`ifcopenshell.open()`	YES	YES	NO (use IfcStore)
`ifcopenshell.api.run()`	YES	YES	YES
`ifcopenshell.geom.create_shape()`	YES	YES	YES
`bpy.data.*`	NO	YES	YES
`bpy.ops.mesh.*`	NO	YES	YES
`bpy.ops.bim.*`	NO	NO	YES
`IfcStore.get_file()`	NO	NO	YES
`tool.Ifc.get_entity()`	NO	NO	YES
Background/headless mode	YES (python)	YES (blender --background)	YES (blender --background)

Version-Specific Routing Rules

Condition	Route To	Reason
IFC4X3 infrastructure entities needed	IfcOpenShell with schema="IFC4X3"	IfcRoad, IfcBridge only in IFC4X3
IFC2X3 file detected	IfcOpenShell with OwnerHistory handling	OwnerHistory is MANDATORY in IFC2X3
Blender 5.0+ drawing code	`gpu` module exclusively	`bgl` module REMOVED in Blender 5.0
Blender 4.0+ context overrides	`context.temp_override()`	Dict-based overrides REMOVED in 4.0
Bonsai v0.8.0+ void operations	`feature.add_feature()`	`void.add_opening()` replaced
IfcBuildingElement vs IfcBuiltElement	Check `model.schema`	IFC4X3 renamed to IfcBuiltElement

Technology Selection by Task Type

Task	Primary Technology	Secondary	Notes
Create IFC from scratch	IfcOpenShell	—	No Blender needed
Validate IFC model	IfcOpenShell	—	`ifcopenshell.validate`
Extract quantities from IFC	IfcOpenShell	—	`ifcopenshell.util.element`
Visualize IFC geometry	IfcOpenShell + Blender	—	`geom.create_shape()` -> bpy mesh
Author BIM model interactively	Bonsai	IfcOpenShell	Bonsai handles sync
Batch enrich IFC files	IfcOpenShell	—	Loop with `pathlib.glob()`
Generate construction drawings	Bonsai	IfcOpenShell	Bonsai drawing module
Clash detection	Bonsai	IfcOpenShell	Bonsai clash module
Quantity takeoff	Bonsai OR IfcOpenShell	—	Bonsai QTO or standalone
IFC to CSV/JSON report	IfcOpenShell	Python stdlib	`ifcopenshell.util.element`
Custom Blender addon with BIM	Blender + Bonsai	IfcOpenShell	Follow Bonsai module pattern
Parametric/generative design	Sverchok	Blender	Node-based visual programming
IFC from parametric geometry	IfcSverchok (Sverchok)	IfcOpenShell	31-node visual IFC pipeline
Building topology analysis	TopologicSverchok	IfcOpenShell	Adjacency, envelope, dual graph
CI/CD model validation	IfcOpenShell	—	Standalone, no GUI

Reference Links

Workflow Methods — Technology-specific workflow entry points and method signatures
End-to-End Examples — Complete orchestrated workflow examples
Anti-Patterns — Cross-technology workflow mistakes to avoid

Dependency Skills

blender-core-api — Blender Python API fundamentals
ifcos-core-concepts — IFC data model and IfcOpenShell concepts
bonsai-core-architecture — Bonsai addon architecture and patterns
aec-core-bim-workflows — Cross-technology BIM workflow patterns

Official Sources

IfcOpenShell Documentation: https://docs.ifcopenshell.org
Bonsai Documentation: https://docs.bonsaibim.org
Blender Python API: https://docs.blender.org/api/current/index.html
IFC4X3 Standard: https://ifc43-docs.standards.buildingsmart.org/
IfcOpenShell GitHub: https://github.com/IfcOpenShell/IfcOpenShell
OSArch Community: https://community.osarch.org

About this skill

Critical Warnings

Quick Reference: Technology Selection Decision Tree

Workflow Patterns

Pattern A: IFC-First Workflow

Pattern B: Blender-First Workflow

Pattern C: Bonsai-Native Workflow

Multi-Step Orchestration: Common AEC Pipelines

Pipeline 1: IFC Creation + Validation + Visualization

Pipeline 2: Multi-File Property Enrichment

Pipeline 3: Blender Model to IFC Export

Pipeline 4: IFC Analysis + Report Generation

Pipeline 5: Bonsai Authoring + Standalone Post-Processing

Technology Bridge Patterns

Bridge 1: IfcOpenShell -> Blender (Geometry Transfer)

Bridge 2: Blender -> IfcOpenShell (Geometry Export)

Bridge 3: Bonsai <-> IfcOpenShell (Bidirectional Entity Access)

Bridge 4: Context Detection (Runtime Environment Probe)

Execution Context Compatibility Matrix

Version-Specific Routing Rules

Technology Selection by Task Type

Reference Links

Dependency Skills

Official Sources