Update config.py

.env.example

@@ -1,4 +0,0 @@
-SPECKLE_TOKEN="mytoken"
-SPECKLE_SERVER_URL="http://127.0.0.1:3000"
-SPECKLE_PROJECT_ID=""
-SPECKLE_AUTOMATION_ID=""

main.py

@@ -1,7 +1,23 @@
-"""This module contains the function's business logic.
+from datetime import datetime
 
-Use the automation_context module to wrap your function in an Automate context helper.
-"""
+import ifcopenshell.api
+
+import utils.config as config
+
+from utils.materials import MaterialManager
+from utils.traversal import traverse, print_tree
+from utils.mapper import classify
+from utils.geometry import mesh_to_ifc, get_display_instances, _make_placement
+from utils.instances import is_instance, instance_to_ifc, build_definition_map, print_instance_stats
+from utils.properties import write_properties, write_common_properties
+from utils.writer import create_ifc_scaffold, StoreyManager
+
+
+SPATIAL_STRUCTURE_TYPES = {
+    "IfcSite", "IfcBuilding", "IfcBuildingStorey",
+    "IfcSpace", "IfcExternalSpatialElement", "IfcSpatialZone",
+    "IfcGrid", "IfcAnnotation",
+}
 
 from pydantic import Field, SecretStr
 from speckle_automate import (
@@ -10,9 +26,6 @@ from speckle_automate import (
     execute_automate_function,
 )
 
-from flatten import flatten_base
-
-
 class FunctionInputs(AutomateBase):
     """These are function author-defined values.
 
@@ -20,77 +33,177 @@ class FunctionInputs(AutomateBase):
     Please use the pydantic model schema to define your inputs:
     https://docs.pydantic.dev/latest/usage/models/
     """
-
-    # An example of how to use secret values.
-    whisper_message: SecretStr = Field(title="This is a secret message")
-    forbidden_speckle_type: str = Field(
-        title="Forbidden speckle type",
-        description=(
-            "If a object has the following speckle_type,"
-            " it will be marked with an error."
-        ),
+    file_name: str = Field(
+        title="File Name",
+        description="The name of the IFC file.",
     )
+    IFC_PROJECT_NAME : str = Field(
+						title="IFC Project Name",
+						description="The name of the IFC project.",
+		)
+    IFC_SITE_NAME : str = Field(
+						title="IFC Site Name",
+						description="The name of the IFC site.",
+		)
+    IFC_BUILDING_NAME : str = Field(
+						title="IFC Building Name",
+						description="The name of the IFC building.",
+		)
 
 
 def automate_function(
     automate_context: AutomationContext,
     function_inputs: FunctionInputs,
 ) -> None:
-    """This is an example Speckle Automate function.
+    print("=" * 60)
+    print("  Speckle -> IFC4.3 Exporter")
+    print("=" * 60)
 
-    Args:
-        automate_context: A context-helper object that carries relevant information
-            about the runtime context of this function.
-            It gives access to the Speckle project data that triggered this run.
-            It also has convenient methods for attaching results to the Speckle model.
-        function_inputs: An instance object matching the defined schema.
-    """
-    # The context provides a convenient way to receive the triggering version.
-    version_root_object = automate_context.receive_version()
+    #version_root_object = automate_context.receive_version()
 
-    objects_with_forbidden_speckle_type = [
-        b
-        for b in flatten_base(version_root_object)
-        if b.speckle_type == function_inputs.forbidden_speckle_type
-    ]
-    count = len(objects_with_forbidden_speckle_type)
+    # ------------------------------------------------------------------ #
+    # 1. Receive
+    # ------------------------------------------------------------------ #
+    base = automate_context.receive_version()
+    scale = 1.0
 
-    if count > 0:
-        # This is how a run is marked with a failure cause.
-        automate_context.attach_error_to_objects(
-            category="Forbidden speckle_type"
-            f" ({function_inputs.forbidden_speckle_type})",
-            affected_objects=objects_with_forbidden_speckle_type,
-            message="This project should not contain the type: "
-            f"{function_inputs.forbidden_speckle_type}",
+    # Uncomment to debug object tree:
+    # print_tree(base)
+
+    # ------------------------------------------------------------------ #
+    # 2. Build definition map (for instance resolution)
+    # ------------------------------------------------------------------ #
+    print("\n🔍 Building definition map...")
+    definition_map = build_definition_map(base)
+
+    # ------------------------------------------------------------------ #
+    # 3. Set up IFC
+    # ------------------------------------------------------------------ #
+    ifc, building, body_context = create_ifc_scaffold()
+    storey_manager = StoreyManager(ifc, building)
+
+    # ------------------------------------------------------------------ #
+    # 3b. Build material map from renderMaterialProxies
+    # ------------------------------------------------------------------ #
+    print("\n🎨 Building material map...")
+    material_manager = MaterialManager(ifc, base)
+
+    # ------------------------------------------------------------------ #
+    # 4. Traverse & export
+    # ------------------------------------------------------------------ #
+    total           = 0
+    no_geometry     = 0
+    skipped_spatial = 0
+    instance_count  = 0
+
+    print(f"\n📐 Processing elements (scale={scale})...\n")
+
+    for obj, level_name, category_name in traverse(base):
+
+        ifc_class = classify(obj, category_name)
+
+        if ifc_class in SPATIAL_STRUCTURE_TYPES:
+            skipped_spatial += 1
+            continue
+
+        name   = getattr(obj, "name", None) or getattr(obj, "applicationId", None) or getattr(obj, "id", "unnamed")
+        storey = storey_manager.get_or_create(level_name)
+
+        # ------------------------------------------------------------------ #
+        # Path A: Instance object (has transform + definitionId, no displayValue)
+        # ------------------------------------------------------------------ #
+        if is_instance(obj):
+            rep, placement = instance_to_ifc(ifc, body_context, obj, definition_map, scale=scale, material_manager=material_manager)
+            element = _create_element(ifc, ifc_class, name, rep, placement, storey)
+            write_common_properties(ifc, element, obj, category_name)
+            write_properties(ifc, element, obj)
+            instance_count += 1
+            total += 1
+            if not rep:
+                no_geometry += 1
+
+        else:
+            # ------------------------------------------------------------------ #
+            # Path B: Normal DataObject — may have:
+            #   B1. Direct mesh geometry in displayValue
+            #   B2. Instance objects in displayValue (the hidden case!)
+            # ------------------------------------------------------------------ #
+
+            # B1: Mesh geometry on the parent object
+            rep, placement = mesh_to_ifc(ifc, body_context, obj, scale=scale, material_manager=material_manager)
+            element = _create_element(ifc, ifc_class, name, rep, placement, storey)
+            write_common_properties(ifc, element, obj, category_name)
+            write_properties(ifc, element, obj)
+            total += 1
+            if not rep:
+                no_geometry += 1
+
+            # B2: Instance objects nested inside displayValue
+            # Each becomes its own IFC element (same class as parent)
+            # Use the parent object's name — the InstanceProxy has no meaningful name
+            nested_instances = get_display_instances(obj)
+            for inst in nested_instances:
+                inst_rep, inst_placement = instance_to_ifc(
+                    ifc, body_context, inst, definition_map, scale=scale, material_manager=material_manager
+                )
+                inst_element = _create_element(
+                    ifc, ifc_class, name, inst_rep, inst_placement, storey
+                )
+                write_common_properties(ifc, inst_element, obj, category_name)
+                write_properties(ifc, inst_element, obj)
+                instance_count += 1
+                total += 1
+                if not inst_rep:
+                    no_geometry += 1
+
+        if total % 100 == 0:
+            print(f"  ... processed {total} elements")
+
+    # ------------------------------------------------------------------ #
+    # 5. Write output
+    # ------------------------------------------------------------------ #
+    file_name = function_inputs.file_name
+    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
+
+    ifc_filename = f"{file_name}_{timestamp}.ifc"
+
+    ifc.write(ifc_filename)
+    automate_context.store_file_result(f"./{ifc_filename}")
+
+    print(f"\n{'=' * 60}")
+    print(f"  Export complete!")
+    print(f"  Total exported     : {total}")
+    print(f"  Instances          : {instance_count}")
+    print(f"  Without geometry   : {no_geometry}")
+    print(f"  Skipped (spatial)  : {skipped_spatial}")
+    print(f"  Storeys created    : {storey_manager.count}")
+    print(f"  Levels             : {', '.join(storey_manager.names)}")
+    print_instance_stats()
+    print(f"{'=' * 60}\n")
+
+def _create_element(ifc, ifc_class, name, rep, placement, storey):
+    """Helper: create an IFC element, assign geometry + placement + container."""
+    element = ifcopenshell.api.run(
+        "root.create_entity", ifc,
+        ifc_class=ifc_class,
+        name=str(name),
+    )
+    if rep and placement:
+        element.Representation = ifc.createIfcProductDefinitionShape(
+            Representations=(rep,)
         )
-        automate_context.mark_run_failed(
-            "Automation failed: "
-            f"Found {count} object that have one of the forbidden speckle types: "
-            f"{function_inputs.forbidden_speckle_type}"
-        )
-
-        # Set the automation context view to the original model/version view
-        # to show the offending objects.
-        automate_context.set_context_view()
-
+        element.ObjectPlacement = placement
+    elif placement:
+        element.ObjectPlacement = placement
     else:
-        automate_context.mark_run_success("No forbidden types found.")
-
-    # If the function generates file results, this is how it can be
-    # attached to the Speckle project/model
-    # automate_context.store_file_result("./report.pdf")
-
-
-def automate_function_without_inputs(automate_context: AutomationContext) -> None:
-    """A function example without inputs.
-
-    If your function does not need any input variables,
-     besides what the automation context provides,
-     the inputs argument can be omitted.
-    """
-    pass
+        element.ObjectPlacement = _make_placement(ifc, 0.0, 0.0, 0.0)
 
+    ifcopenshell.api.run(
+        "spatial.assign_container", ifc,
+        relating_structure=storey,
+        products=[element],
+    )
+    return element
 
 # make sure to call the function with the executor
 if __name__ == "__main__":

pyproject.toml

@@ -9,13 +9,15 @@ readme = "README.md"
 license = "Apache-2.0"
 keywords = ["speckle", "automate", "bim", "aec"]
 
-dependencies = ["specklepy==3.1.0"]
+dependencies = ["specklepy==3.1.0",
+		"ifcopenshell==0.8.4.post1",]
 
 [project.optional-dependencies]
 dev = [
     "mypy==1.13.0",
     "pytest==7.4.4",
     "ruff==0.11.12",
+
 ]
 
 [tool.ruff]

tests/test_function.py

@@ -23,8 +23,10 @@ def test_function_run(
         automation_context,
         automate_function,
         FunctionInputs(
-            forbidden_speckle_type="None",
-            whisper_message=SecretStr("testing automatically"),
+            file_name="test_output.ifc",
+            IFC_PROJECT_NAME = "Speckle Export",
+            IFC_SITE_NAME = "Site",
+            IFC_BUILDING_NAME = "Building"
         ),
     )
 

utils/config.py

@@ -0,0 +1,34 @@
+# =============================================================================
+# config.py
+# All user-facing settings. Edit this file before running main.py.
+# =============================================================================
+
+# --- Speckle Connection ---
+SPECKLE_HOST = "app.speckle.systems"   # or your self-hosted server URL
+SPECKLE_TOKEN = "****"  # from app.speckle.systems/profile
+
+# --- Speckle Project ---
+PROJECT_ID = "d7d987146d"         # the stream/project ID from the URL
+VERSION_ID = "d59178f01e"         # the specific version/commit to export
+
+# --- IFC Output ---
+OUTPUT_PATH = "output3.ifc"             # where to write the IFC file
+IFC_SCHEMA = "IFC4X3"                  # IFC4X3 = IFC4.3
+
+# --- Project Metadata (written into the IFC file) ---
+IFC_PROJECT_NAME = "Speckle Export"
+IFC_SITE_NAME = "Site"
+IFC_BUILDING_NAME = "Building"
+
+# --- Units ---
+# Speckle unit → metres scale factor
+# The exporter reads units from the root object automatically,
+# but this is the fallback if units are not set on the stream.
+DEFAULT_UNITS = "mm"
+UNIT_SCALE = {
+    "mm": 0.001,
+    "cm": 0.01,
+    "m":  1.0,
+    "ft": 0.3048,
+    "in": 0.0254,
+}

utils/geometry.py

@@ -0,0 +1,465 @@
+# =============================================================================
+# geometry.py
+# Converts Speckle DataObject geometry → IFC IfcFacetedBrep + IfcLocalPlacement
+#
+# Key facts:
+#   - After specklepy receive(), vertices and faces are FLAT Python lists
+#   - displayValue is an array of Mesh objects
+#   - Units are in mm (for Revit), scale to metres for IFC
+#   - Vertices are in absolute world coordinates
+# =============================================================================
+
+import ifcopenshell
+from specklepy.objects.base import Base
+
+
+# Scale factors → MILLIMETRES (IFC file is declared as mm)
+_UNIT_SCALES = {
+    "mm": 1.0,    "millimeter": 1.0,    "millimeters": 1.0,
+    "cm": 10.0,   "centimeter": 10.0,   "centimeters": 10.0,
+    "m":  1000.0, "meter": 1000.0,      "meters": 1000.0,
+    "ft": 304.8,  "foot": 304.8,        "feet": 304.8,
+    "in": 25.4,   "inch": 25.4,         "inches": 25.4,
+}
+
+
+# --------------------------------------------------------------------------- #
+# Geometry validation helpers (GEM111 + BRP002 fixes)
+# --------------------------------------------------------------------------- #
+
+# Minimum distance in mm below which two vertices are considered identical (GEM111).
+_VERTEX_MERGE_TOL = 0.01  # 0.01 mm
+
+
+def snap_coord(v: float) -> int:
+    """Snap a coordinate to integer grid at _VERTEX_MERGE_TOL resolution."""
+    return round(v / _VERTEX_MERGE_TOL)
+
+
+def _find_connected_components(snapped_faces: list) -> list:
+    """
+    Union-Find: group face indices into connected components.
+    Two faces are connected if they share an edge (pair of snapped vertex keys).
+    Returns list of components, each a list of face indices.
+
+    BRP002 requires all faces in an IfcClosedShell to form ONE component.
+    If multiple components exist, each must become a separate IfcClosedShell.
+    """
+    n = len(snapped_faces)
+    if n == 0:
+        return []
+
+    parent = list(range(n))
+
+    def find(x):
+        while parent[x] != x:
+            parent[x] = parent[parent[x]]
+            x = parent[x]
+        return x
+
+    def union(a, b):
+        parent[find(a)] = find(b)
+
+    # Map each edge to the first face that used it, then union subsequent faces
+    edge_to_face = {}
+    for fi, keys in enumerate(snapped_faces):
+        for i in range(len(keys)):
+            edge = frozenset([keys[i], keys[(i + 1) % len(keys)]])
+            if edge in edge_to_face:
+                union(fi, edge_to_face[edge])
+            else:
+                edge_to_face[edge] = fi
+
+    from collections import defaultdict
+    groups: dict = defaultdict(list)
+    for fi in range(n):
+        groups[find(fi)].append(fi)
+    return list(groups.values())
+
+
+def build_ifc_breps(ifc, verts_scaled: list, face_groups: list) -> list:
+    """
+    Build a list of IfcFacetedBrep from scaled (x,y,z) vertices and face index groups.
+
+    GEM111 fix: skip faces with near-duplicate vertices (snapped to same grid cell).
+    BRP002 fix: split faces into connected components; each component → its own
+                IfcClosedShell → IfcFacetedBrep so every shell is arc-wise connected.
+
+    verts_scaled: flat list of already-scaled floats [x0,y0,z0, x1,y1,z1, ...]
+    face_groups:  list of index lists [[i,j,k], [i,j,k,l], ...]
+    Returns: list of IfcFacetedBrep (one per connected component, never empty).
+    """
+    # Pass 1: validate faces and build snapped key lists for connectivity analysis
+    valid_faces = []    # list of (pts_raw, snapped_keys)
+    for indices in face_groups:
+        try:
+            pts_raw = []
+            snapped = []
+            degenerate = False
+            seen = set()
+
+            for i in indices:
+                x = float(verts_scaled[i * 3])
+                y = float(verts_scaled[i * 3 + 1])
+                z = float(verts_scaled[i * 3 + 2])
+                key = (snap_coord(x), snap_coord(y), snap_coord(z))
+                if key in seen:
+                    degenerate = True
+                    break
+                seen.add(key)
+                pts_raw.append((x, y, z))
+                snapped.append(key)
+
+            if degenerate or len(pts_raw) < 3:
+                continue
+
+            valid_faces.append((pts_raw, snapped))
+        except Exception:
+            continue
+
+    if not valid_faces:
+        return []
+
+    # Pass 2: split into connected components (BRP002)
+    snapped_only = [f[1] for f in valid_faces]
+    components = _find_connected_components(snapped_only)
+
+    # Pass 3: build one IfcFacetedBrep per component
+    breps = []
+    for component_indices in components:
+        ifc_faces = []
+        for fi in component_indices:
+            pts_raw, _ = valid_faces[fi]
+            try:
+                pts = [ifc.createIfcCartesianPoint([x, y, z]) for x, y, z in pts_raw]
+                poly  = ifc.createIfcPolyLoop(pts)
+                bound = ifc.createIfcFaceOuterBound(poly, True)
+                ifc_faces.append(ifc.createIfcFace([bound]))
+            except Exception:
+                continue
+
+        if not ifc_faces:
+            continue
+
+        shell = ifc.createIfcClosedShell(ifc_faces)
+        breps.append(ifc.createIfcFacetedBrep(shell))
+
+    return breps
+
+
+# Keep old name as alias so instances.py import works unchanged
+def build_ifc_faces(ifc, verts_scaled: list, face_groups: list) -> list:
+    """Legacy wrapper — returns flat list of IfcFace (no connectivity splitting)."""
+    # Used only as a fallback; callers should prefer build_ifc_breps directly.
+    breps = build_ifc_breps(ifc, verts_scaled, face_groups)
+    # Return the faces from all shells combined (for callers that need face lists)
+    faces = []
+    for brep in breps:
+        faces.extend(brep.Outer.CfsFaces)
+    return faces
+
+
+# --------------------------------------------------------------------------- #
+# Safe data access helpers
+# --------------------------------------------------------------------------- #
+
+def _get(obj, key, default=None):
+    """
+    Safe access for specklepy Base objects.
+    Tries attribute access first, then bracket access.
+    """
+    try:
+        val = getattr(obj, key, None)
+        if val is not None:
+            return val
+    except Exception:
+        pass
+    try:
+        val = obj[key]
+        if val is not None:
+            return val
+    except Exception:
+        pass
+    return default
+
+
+def unwrap_chunks(raw) -> list:
+    """
+    Flatten a Speckle data array into a plain Python list of numbers.
+
+    Handles two cases:
+      1. Already flat list of numbers (after specklepy receive deserializes)
+         → [3, 0, 1, 2, 3, ...] returned as-is
+      2. List of DataChunk objects (raw from server before deserialization)
+         → each chunk's .data list is concatenated
+
+    Both cases are handled so this function is always safe to call.
+    """
+    if not raw:
+        return []
+
+    result = []
+    for item in raw:
+        if item is None:
+            continue
+        # Plain number — already flat
+        if isinstance(item, (int, float)):
+            result.append(item)
+            continue
+        # DataChunk — unwrap .data
+        speckle_type = getattr(item, "speckle_type", "") or ""
+        if "DataChunk" in speckle_type:
+            chunk_data = _get(item, "data") or _get(item, "@data")
+            if chunk_data:
+                result.extend(list(chunk_data))
+        else:
+            # Unknown — try iterating (handles nested lists)
+            try:
+                result.extend(list(item))
+            except Exception:
+                pass
+    return result
+
+
+def _resolve_scale(obj, stream_scale: float) -> float:
+    """Resolve unit scale: obj.units → stream fallback."""
+    units = _get(obj, "units")
+    if units and isinstance(units, str):
+        return _UNIT_SCALES.get(units.lower().strip(), stream_scale)
+    return stream_scale
+
+
+# --------------------------------------------------------------------------- #
+# Mesh extraction
+# --------------------------------------------------------------------------- #
+
+def _is_mesh(item) -> bool:
+    """
+    Detect if a specklepy object is a Mesh.
+    Uses speckle_type string — more reliable than hasattr on Base objects.
+    """
+    if item is None:
+        return False
+    speckle_type = _get(item, "speckle_type") or ""
+    if "Mesh" in speckle_type:
+        return True
+    # Fallback: has both vertices and faces data
+    verts = _get(item, "vertices")
+    faces = _get(item, "faces")
+    return verts is not None and faces is not None
+
+
+def get_display_meshes(obj: Base) -> list:
+    """
+    Extract all Mesh objects from a DataObject's displayValue.
+    displayValue is always an array per the Speckle schema docs.
+    """
+    meshes = []
+
+    for key in ["displayValue", "@displayValue"]:
+        display = _get(obj, key)
+        if display is None:
+            continue
+        items = display if isinstance(display, list) else [display]
+        for item in items:
+            if _is_mesh(item):
+                meshes.append(item)
+        if meshes:
+            break  # found meshes, don't check @displayValue too
+
+    # Fallback: object itself is a Mesh
+    if not meshes and _is_mesh(obj):
+        speckle_type = _get(obj, "speckle_type") or ""
+        if "Mesh" in speckle_type:
+            meshes.append(obj)
+
+    return meshes
+
+
+def get_display_instances(obj: Base) -> list:
+    """
+    Extract InstanceProxy objects from a DataObject's displayValue.
+
+    Per the official speckleifc converter, every IFC element's displayValue
+    contains InstanceProxy objects (not raw meshes). Each InstanceProxy has:
+      - transform:    16-float row-major matrix, translation in metres
+      - definitionId: "DEFINITION:{meshAppId}" string
+      - units:        "m"
+
+    Raw meshes do NOT appear in displayValue in IFC→Speckle exports.
+    """
+    instances = []
+    for key in ["displayValue", "@displayValue"]:
+        display = _get(obj, key)
+        if display is None:
+            continue
+        items = display if isinstance(display, list) else [display]
+        for item in items:
+            if item is None:
+                continue
+            transform     = _get(item, "transform")
+            definition_id = _get(item, "definitionId")
+            if transform is not None and definition_id is not None:
+                instances.append(item)
+        if instances:
+            break
+    return instances
+
+
+# --------------------------------------------------------------------------- #
+# Face decoding
+# --------------------------------------------------------------------------- #
+
+def decode_faces(faces_raw: list) -> list:
+    """
+    Decode Speckle's run-length encoded face list into vertex index groups.
+    Format: [n, i0, i1, ..., n, i0, i1, ...]
+      n=0 → triangle (legacy), n=1 → quad (legacy), n≥3 → n-gon
+    """
+    decoded = []
+    i = 0
+    while i < len(faces_raw):
+        n = int(faces_raw[i])
+        if n == 0:
+            n = 3
+        elif n == 1:
+            n = 4
+        end = i + 1 + n
+        if end > len(faces_raw):
+            break
+        indices = [int(faces_raw[i + 1 + j]) for j in range(n)]
+        decoded.append(indices)
+        i = end
+    return decoded
+
+
+# --------------------------------------------------------------------------- #
+# Bounding box + placement
+# --------------------------------------------------------------------------- #
+
+def compute_origin(flat_verts: list) -> tuple:
+    """
+    Compute placement origin from scaled vertex list (metres).
+    X, Y = bounding box centroid
+    Z = minimum Z (bottom face of element — more natural for IFC)
+    """
+    xs = flat_verts[0::3]
+    ys = flat_verts[1::3]
+    zs = flat_verts[2::3]
+    cx = (min(xs) + max(xs)) / 2.0
+    cy = (min(ys) + max(ys)) / 2.0
+    cz = min(zs)
+    return cx, cy, cz
+
+
+def _make_placement(ifc, x: float, y: float, z: float):
+    """Create an IfcLocalPlacement at absolute world coordinates (metres)."""
+    origin = ifc.createIfcCartesianPoint([x, y, z])
+    z_axis = ifc.createIfcDirection([0.0, 0.0, 1.0])
+    x_axis = ifc.createIfcDirection([1.0, 0.0, 0.0])
+    a2p    = ifc.createIfcAxis2Placement3D(origin, z_axis, x_axis)
+    return ifc.createIfcLocalPlacement(PlacementRelTo=None, RelativePlacement=a2p)
+
+
+# --------------------------------------------------------------------------- #
+# Main conversion
+# --------------------------------------------------------------------------- #
+
+def mesh_to_ifc(
+    ifc: ifcopenshell.file,
+    body_context,
+    obj: Base,
+    scale: float = 0.001,
+    material_manager=None,
+) -> tuple:
+    """
+    Convert a Speckle DataObject → (IfcShapeRepresentation, IfcLocalPlacement).
+    Creates one IfcFacetedBrep per mesh so each can carry its own material style.
+    Returns (None, None) if no usable geometry is found.
+    """
+    meshes = get_display_meshes(obj)
+    if not meshes:
+        return None, None
+
+    obj_scale = _resolve_scale(obj, scale)
+
+    # ------------------------------------------------------------------ #
+    # Pass 1: collect all scaled vertices to compute world origin
+    # ------------------------------------------------------------------ #
+    all_scaled = []
+    for mesh in meshes:
+        raw_verts = _get(mesh, "vertices") or []
+        verts = unwrap_chunks(list(raw_verts))
+        if not verts:
+            continue
+        ms = _resolve_scale(mesh, obj_scale)
+        for i in range(0, len(verts) - 2, 3):
+            all_scaled.extend([
+                float(verts[i])   * ms,
+                float(verts[i+1]) * ms,
+                float(verts[i+2]) * ms,
+            ])
+
+    if not all_scaled:
+        return None, None
+
+    ox, oy, oz = compute_origin(all_scaled)
+
+    # ------------------------------------------------------------------ #
+    # Pass 2: one brep per mesh (so each can have its own material style)
+    # ------------------------------------------------------------------ #
+    brep_items = []
+
+    for mesh in meshes:
+        raw_verts = _get(mesh, "vertices") or []
+        raw_faces = _get(mesh, "faces") or []
+        verts     = unwrap_chunks(list(raw_verts))
+        faces_raw = unwrap_chunks(list(raw_faces))
+
+        if not verts or not faces_raw:
+            continue
+
+        ms = _resolve_scale(mesh, obj_scale)
+
+        try:
+            face_groups = decode_faces(faces_raw)
+        except Exception as e:
+            print(f"  ⚠️  Face decode error: {e}")
+            continue
+
+        # Build pre-scaled vertex list (relative to origin) for this mesh
+        verts_scaled = []
+        for vi in range(0, len(verts) - 2, 3):
+            verts_scaled.append(float(verts[vi])   * ms - ox)
+            verts_scaled.append(float(verts[vi+1]) * ms - oy)
+            verts_scaled.append(float(verts[vi+2]) * ms - oz)
+
+        mesh_breps = build_ifc_breps(ifc, verts_scaled, face_groups)
+
+        if not mesh_breps:
+            continue
+
+        # Apply material style to every component brep of this mesh
+        if material_manager:
+            mesh_app_id = _get(mesh, "applicationId")
+            if mesh_app_id:
+                for brep in mesh_breps:
+                    material_manager.apply_to_item(brep, str(mesh_app_id))
+
+        brep_items.extend(mesh_breps)
+
+    if not brep_items:
+        return None, None
+
+    # ------------------------------------------------------------------ #
+    # Assemble IfcShapeRepresentation + IfcLocalPlacement
+    # ------------------------------------------------------------------ #
+    rep = ifc.createIfcShapeRepresentation(
+        ContextOfItems=body_context,
+        RepresentationIdentifier="Body",
+        RepresentationType="Brep",
+        Items=brep_items,
+    )
+    placement = _make_placement(ifc, ox, oy, oz)
+
+    return rep, placement

utils/instances.py

@@ -0,0 +1,373 @@
+# =============================================================================
+# instances.py
+# Handles Speckle InstanceProxy objects from both:
+#
+# FORMAT A — Revit connector (our actual use case):
+#   _units      = "mm"
+#   transform   = 16 floats, row-major, translation in MM
+#   definitionId = 64-char uppercase hex hash (matches object id[:32] in tree)
+#   The definition object lives somewhere in the object tree.
+#
+# FORMAT B — speckleifc IFC→Speckle converter:
+#   units       = "m"
+#   transform   = 16 floats, row-major, translation in METRES
+#   definitionId = "DEFINITION:{meshAppId}"
+#   Definition geometry lives in root → Collection("definitionGeometry")
+#
+# We detect the format by the definitionId prefix.
+# =============================================================================
+
+from specklepy.objects.base import Base
+from utils.geometry import _get, unwrap_chunks, decode_faces, _UNIT_SCALES, build_ifc_breps
+
+
+def is_instance(obj) -> bool:
+    """Returns True if this object is a Speckle InstanceProxy."""
+    return _get(obj, "transform") is not None and _get(obj, "definitionId") is not None
+
+
+def _is_ifc_format(definition_id: str) -> bool:
+    """True if this is speckleifc format (definitionId starts with 'DEFINITION:')."""
+    return definition_id.startswith("DEFINITION:")
+
+
+def build_definition_map(root: Base) -> dict:
+    """
+    Build a unified definition map that handles both formats.
+
+    Returns dict with keys:
+      "by_id"       : {obj_id_lower[:32] → object}   for Revit format
+      "by_app_id"   : {applicationId_lower → object}  for Revit format
+      "ifc_proxies" : {"DEFINITION:xxx" → proxy}      for IFC format
+      "ifc_meshes"  : {meshAppId → Mesh}               for IFC format
+    """
+    by_id      = {}
+    by_app_id  = {}
+    ifc_proxies = {}
+    ifc_meshes  = {}
+
+    # --- Walk entire tree for Revit format ---
+    _collect_all(root, by_id, by_app_id, depth=0)
+
+    # --- Extract speckleifc structures for IFC format ---
+    proxies_raw = _get(root, "instanceDefinitionProxies")
+    if proxies_raw:
+        for proxy in (proxies_raw if isinstance(proxies_raw, list) else [proxies_raw]):
+            app_id = _get(proxy, "applicationId")
+            if app_id:
+                ifc_proxies[app_id] = proxy            # original case (for IFC format)
+                ifc_proxies[app_id.lower()] = proxy    # lowercase (for Revit format)
+
+    elements = _get(root, "elements") or _get(root, "@elements") or []
+    for child in (elements if isinstance(elements, list) else []):
+        if (_get(child, "name") or "") == "definitionGeometry":
+            geom_elements = _get(child, "elements") or _get(child, "@elements") or []
+            for mesh in (geom_elements if isinstance(geom_elements, list) else []):
+                mesh_app_id = _get(mesh, "applicationId")
+                if mesh_app_id:
+                    ifc_meshes[mesh_app_id] = mesh
+
+    print(f"   Objects indexed by id:     {len(by_id)}")
+    print(f"   Objects indexed by appId:  {len(by_app_id)}")
+    print(f"   IFC definition proxies:    {len(ifc_proxies)}")
+    print(f"   IFC definition meshes:     {len(ifc_meshes)}")
+
+    # Diagnostic: dump first 3 instanceDefinitionProxies to understand structure
+    print("\n   [PROXY DIAG] First 3 instanceDefinitionProxies from root:")
+    proxies_raw2 = _get(root, "instanceDefinitionProxies")
+    if proxies_raw2:
+        sample = proxies_raw2 if isinstance(proxies_raw2, list) else [proxies_raw2]
+        for i, proxy in enumerate(sample[:3]):
+            app_id  = _get(proxy, "applicationId") or "?"
+            name    = _get(proxy, "name") or "?"
+            objects = _get(proxy, "objects") or []
+            obj_ids = list(objects)[:3] if objects else []
+            print(f"   [{i}] appId={app_id}")
+            print(f"        name={name}")
+            print(f"        objects={obj_ids} (len={len(list(objects)) if objects else 0})")
+            # Check if first object is found in our maps
+            if obj_ids:
+                oid = str(obj_ids[0])
+                in_by_id     = oid.lower()[:32] in by_id
+                in_by_app_id = oid.lower() in by_app_id
+                print(f"        objects[0]='{oid}' → in by_id: {in_by_id}, in by_app_id: {in_by_app_id}")
+    else:
+        print("   [PROXY DIAG] No instanceDefinitionProxies found on root!")
+        # Check where they might be
+        for key in ["@instanceDefinitionProxies", "instancedefinitionproxies"]:
+            val = _get(root, key)
+            if val:
+                print(f"   Found under key '{key}': {type(val)}")
+
+    return {
+        "by_id":       by_id,
+        "by_app_id":   by_app_id,
+        "ifc_proxies": ifc_proxies,
+        "ifc_meshes":  ifc_meshes,
+    }
+
+
+def _collect_all(obj, by_id: dict, by_app_id: dict, depth: int):
+    if obj is None or depth > 25:
+        return
+
+    obj_id = _get(obj, "id")
+    if obj_id and isinstance(obj_id, str):
+        key = obj_id.lower()
+        by_id[key] = obj
+        # Also store truncated — definitionId (64 chars) matches id (32 chars)
+        if len(key) == 32:
+            by_id[key] = obj
+        elif len(key) > 32:
+            by_id[key[:32]] = obj
+
+    app_id = _get(obj, "applicationId")
+    if app_id and isinstance(app_id, str):
+        by_app_id[app_id.lower()] = obj
+
+    for key in ["elements", "@elements", "displayValue", "@displayValue",
+                "objects", "@objects", "definition", "@definition"]:
+        try:
+            children = obj[key]
+            if children is None:
+                continue
+            if not isinstance(children, list):
+                children = [children]
+            for child in children:
+                _collect_all(child, by_id, by_app_id, depth + 1)
+        except Exception:
+            continue
+
+
+def _get_revit_meshes(definition_id: str, definition_map: dict) -> list:
+    """
+    Revit format:
+      definitionId (64-char hex) → InstanceDefinitionProxy.applicationId
+      proxy.objects[0] is a UUID applicationId → find mesh by applicationId
+    """
+    from utils.geometry import get_display_meshes
+
+    # Step 1: find the InstanceDefinitionProxy by its applicationId (case-insensitive)
+    ifc_proxies = definition_map.get("ifc_proxies", {})
+    proxy = ifc_proxies.get(definition_id) or ifc_proxies.get(definition_id.lower())
+    if proxy is None:
+        return []
+
+    # Step 2: get the mesh applicationIds from proxy.objects
+    object_ids = _get(proxy, "objects") or []
+    if not isinstance(object_ids, list):
+        object_ids = list(object_ids)
+
+    # Step 3: look up each mesh by applicationId
+    by_app_id = definition_map.get("by_app_id", {})
+    meshes = []
+    for oid in object_ids:
+        obj = by_app_id.get(str(oid).lower())
+        if obj is not None:
+            # The found object may itself be a mesh, or contain displayValue meshes
+            found_meshes = get_display_meshes(obj)
+            if found_meshes:
+                meshes.extend(found_meshes)
+            else:
+                # It IS the mesh directly
+                meshes.append(obj)
+    return meshes
+
+
+def _get_ifc_meshes(definition_id: str, definition_map: dict) -> list:
+    """
+    IFC format: definitionId = "DEFINITION:224058_mat0"
+    Look up proxy → objects list → meshes from ifc_meshes dict.
+    """
+    ifc_proxies = definition_map.get("ifc_proxies", {})
+    ifc_meshes  = definition_map.get("ifc_meshes", {})
+
+    proxy = ifc_proxies.get(definition_id)
+    if proxy is None:
+        return []
+
+    object_ids = _get(proxy, "objects") or []
+    result = []
+    for oid in (object_ids if isinstance(object_ids, list) else [object_ids]):
+        mesh = ifc_meshes.get(str(oid))
+        if mesh is not None:
+            result.append(mesh)
+    return result
+
+
+def _resolve_instance_scale(obj, stream_scale: float) -> float:
+    """
+    Resolve scale for the transform translation.
+    Tries bracket access for '_units' (Revit uses underscore).
+    IFC format instances have units="m" → scale=1.0 (no scaling).
+    """
+    for key in ["units", "_units"]:
+        try:
+            units = obj[key]
+            if units and isinstance(units, str):
+                s = _UNIT_SCALES.get(units.lower().strip())
+                if s is not None:
+                    return s
+        except Exception:
+            pass
+    return stream_scale
+
+
+def _parse_transform(t: list, scale: float) -> tuple:
+    """
+    Row-major 4x4 matrix.
+    Translation at t[3], t[7], t[11] — scaled to metres.
+    Local X axis = row 0, Local Z axis = row 2.
+    """
+    tx = float(t[3])  * scale
+    ty = float(t[7])  * scale
+    tz = float(t[11]) * scale
+    x_axis = (float(t[0]), float(t[1]), float(t[2]))
+    z_axis = (float(t[8]), float(t[9]), float(t[10]))
+    return (tx, ty, tz), x_axis, z_axis
+
+
+def _make_ifc_placement(ifc, tx, ty, tz, x_axis, z_axis):
+    origin = ifc.createIfcCartesianPoint([tx, ty, tz])
+    x_dir  = ifc.createIfcDirection(list(x_axis))
+    z_dir  = ifc.createIfcDirection(list(z_axis))
+    a2p    = ifc.createIfcAxis2Placement3D(origin, z_dir, x_dir)
+    return ifc.createIfcLocalPlacement(PlacementRelTo=None, RelativePlacement=a2p)
+
+
+# Stats
+_stats   = {"found": 0, "not_found": 0}
+_dbg_cnt = [0]
+
+
+_MM_SCALES = {
+    "mm": 1.0, "millimeter": 1.0, "millimeters": 1.0,
+    "cm": 10.0, "centimeter": 10.0,
+    "m": 1000.0, "meter": 1000.0, "meters": 1000.0,
+    "ft": 304.8, "in": 25.4,
+}
+
+
+def _apply_transform(t: list, vx: float, vy: float, vz: float, ts: float) -> tuple:
+    """
+    Apply a row-major 4x4 transform to a single vertex.
+    ts = scale factor applied to the translation components only (not rotation).
+    For Revit mm data with IFC in mm: ts=1.0 (no conversion).
+    For IFC-format transforms (metres): ts=1000.0 (m→mm).
+    Rotation components are dimensionless and never scaled.
+    """
+    x = t[0]*vx + t[1]*vy + t[2]*vz  + t[3]  * ts
+    y = t[4]*vx + t[5]*vy + t[6]*vz  + t[7]  * ts
+    z = t[8]*vx + t[9]*vy + t[10]*vz + t[11] * ts
+    return x, y, z
+
+
+def instance_to_ifc(ifc, body_context, obj: Base, definition_map: dict,
+                    scale: float = 1.0, material_manager=None):
+    """
+    Convert a Speckle InstanceProxy → (IfcShapeRepresentation, IfcLocalPlacement).
+
+    Strategy: BAKE the full 4x4 transform into every vertex (world coordinates).
+    Creates one IfcFacetedBrep per definition mesh so each can carry its own
+    material style via renderMaterialProxies.
+    """
+    transform_raw = _get(obj, "transform")
+    if not transform_raw:
+        return None, None
+    t = list(transform_raw)
+    if len(t) != 16:
+        return None, None
+
+    definition_id = _get(obj, "definitionId") or ""
+    ifc_format    = _is_ifc_format(definition_id)
+
+    # Translation scale: IFC format transform is in metres → convert to mm
+    # Revit format transform is already in mm (same as IFC file units)
+    ts = 1000.0 if ifc_format else _resolve_instance_scale(obj, scale)
+
+    if _dbg_cnt[0] < 6:
+        _dbg_cnt[0] += 1
+        fmt = "IFC" if ifc_format else "Revit"
+        x_axis = (round(t[0],2), round(t[1],2), round(t[2],2))
+        z_axis = (round(t[8],2), round(t[9],2), round(t[10],2))
+        print(f"  [INST {_dbg_cnt[0]} {fmt}] {definition_id[:40]}")
+        print(f"    t[3]={t[3]:.1f} t[7]={t[7]:.1f} t[11]={t[11]:.1f}  x={x_axis}  z={z_axis}")
+
+    # World-origin placement (geometry is baked to world coords)
+    origin    = ifc.createIfcCartesianPoint([0.0, 0.0, 0.0])
+    a2p       = ifc.createIfcAxis2Placement3D(origin, None, None)
+    placement = ifc.createIfcLocalPlacement(PlacementRelTo=None, RelativePlacement=a2p)
+
+    # Get definition meshes
+    if ifc_format:
+        meshes = _get_ifc_meshes(definition_id, definition_map)
+    else:
+        meshes = _get_revit_meshes(definition_id, definition_map)
+
+    if not meshes:
+        _stats["not_found"] += 1
+        return None, placement
+
+    _stats["found"] += 1
+
+    # One brep per mesh so each can have its own material style
+    brep_items = []
+    for mesh in meshes:
+        raw_verts = _get(mesh, "vertices") or []
+        raw_faces = _get(mesh, "faces") or []
+        verts     = unwrap_chunks(list(raw_verts))
+        faces_raw = unwrap_chunks(list(raw_faces))
+        if not verts or not faces_raw:
+            continue
+
+        mesh_units = _get(mesh, "units") or _get(mesh, "_units") or ("m" if ifc_format else "mm")
+        ms = _MM_SCALES.get(mesh_units.lower().strip(), 1.0)
+
+        try:
+            face_groups = decode_faces(faces_raw)
+        except Exception as e:
+            print(f"  ⚠️  Instance face decode: {e}")
+            continue
+
+        # Pre-compute world coords for all vertices in this mesh
+        verts_world = []
+        for vi in range(0, len(verts) - 2, 3):
+            lx = float(verts[vi])   * ms
+            ly = float(verts[vi+1]) * ms
+            lz = float(verts[vi+2]) * ms
+            wx, wy, wz = _apply_transform(t, lx, ly, lz, ts)
+            verts_world.append(wx)
+            verts_world.append(wy)
+            verts_world.append(wz)
+
+        mesh_breps = build_ifc_breps(ifc, verts_world, face_groups)
+
+        if not mesh_breps:
+            continue
+
+        # Apply material style to every component brep of this mesh
+        if material_manager:
+            mesh_app_id = _get(mesh, "applicationId")
+            if mesh_app_id:
+                for brep in mesh_breps:
+                    material_manager.apply_to_item(brep, str(mesh_app_id))
+
+        brep_items.extend(mesh_breps)
+
+    if not brep_items:
+        return None, placement
+
+    rep = ifc.createIfcShapeRepresentation(
+        ContextOfItems=body_context,
+        RepresentationIdentifier="Body",
+        RepresentationType="Brep",
+        Items=brep_items,
+    )
+    return rep, placement
+
+
+def print_instance_stats():
+    total = _stats["found"] + _stats["not_found"]
+    print(f"  Instance resolution: {_stats['found']}/{total} definitions found")
+    if _stats["not_found"] > 0:
+        print(f"  ⚠️  {_stats['not_found']} instances had no definition geometry")

utils/mapper.py

@@ -0,0 +1,137 @@
+# =============================================================================
+# mapper.py
+# Maps Speckle speckle_type strings and Revit category names → IFC entity classes.
+#
+# Strategy:
+#   1. Try to match speckle_type exactly or by prefix
+#   2. Fall back to Revit category name (e.g. "Floors" → IfcSlab)
+#   3. Fall back to IfcBuildingElementProxy if nothing matches
+# =============================================================================
+
+
+# --- speckle_type → IFC class ---
+# Covers Objects.BuiltElements.* from the Speckle Objects kit
+SPECKLE_TYPE_MAP: dict[str, str] = {
+    "Objects.BuiltElements.Wall":                        "IfcWall",
+    "Objects.BuiltElements.Floor":                       "IfcSlab",
+    "Objects.BuiltElements.Roof":                        "IfcRoof",
+    "Objects.BuiltElements.Column":                      "IfcColumn",
+    "Objects.BuiltElements.Beam":                        "IfcBeam",
+    "Objects.BuiltElements.Brace":                       "IfcMember",
+    "Objects.BuiltElements.Duct":                        "IfcDuctSegment",
+    "Objects.BuiltElements.Pipe":                        "IfcPipeSegment",
+    "Objects.BuiltElements.Wire":                        "IfcCableCarrierSegment",
+    "Objects.BuiltElements.Opening":                     "IfcOpeningElement",
+    "Objects.BuiltElements.Room":                        "IfcSpace",
+    "Objects.BuiltElements.Ceiling":                     "IfcCovering",
+    "Objects.BuiltElements.Stair":                       "IfcStair",
+    "Objects.BuiltElements.Ramp":                        "IfcRamp",
+    "Objects.BuiltElements.Foundation":                  "IfcFooting",
+    "Objects.BuiltElements.Grid":                        "IfcGrid",
+    "Objects.BuiltElements.Level":                       "IfcBuildingStorey",
+    "Objects.BuiltElements.Revit.RevitWall":             "IfcWall",
+    "Objects.BuiltElements.Revit.RevitFloor":            "IfcSlab",
+    "Objects.BuiltElements.Revit.RevitRoof":             "IfcRoof",
+    "Objects.BuiltElements.Revit.RevitColumn":           "IfcColumn",
+    "Objects.BuiltElements.Revit.RevitBeam":             "IfcBeam",
+    "Objects.BuiltElements.Revit.RevitBrace":            "IfcMember",
+    "Objects.BuiltElements.Revit.RevitDuct":             "IfcDuctSegment",
+    "Objects.BuiltElements.Revit.RevitPipe":             "IfcPipeSegment",
+    "Objects.BuiltElements.Revit.RevitRoom":             "IfcSpace",
+    "Objects.BuiltElements.Revit.RevitStair":            "IfcStair",
+    "Objects.BuiltElements.Revit.RevitRailing":          "IfcRailing",
+    "Objects.BuiltElements.Revit.RevitCeiling":          "IfcCovering",
+    "Objects.BuiltElements.Revit.RevitTopography":       "IfcGeographicElement",
+    "Objects.BuiltElements.Revit.RevitElementType":      "IfcBuildingElementProxy",
+    "Objects.Geometry.Mesh":                             "IfcBuildingElementProxy",
+    "Objects.Geometry.Brep":                             "IfcBuildingElementProxy",
+}
+
+# --- Revit category name → IFC class (fallback) ---
+CATEGORY_MAP: dict[str, str] = {
+    "Walls":                        "IfcWall",
+    "Floors":                       "IfcSlab",
+    "Roofs":                        "IfcRoof",
+    "Structural Columns":           "IfcColumn",
+    "Columns":                      "IfcColumn",
+    "Structural Framing":           "IfcBeam",
+    "Beams":                        "IfcBeam",
+    "Ducts":                        "IfcDuctSegment",
+    "Pipes":                        "IfcPipeSegment",
+    "Conduits":                     "IfcCableCarrierSegment",
+    "Cable Trays":                  "IfcCableCarrierSegment",
+    "Rooms":                        "IfcSpace",
+    "Spaces":                       "IfcSpace",
+    "Ceilings":                     "IfcCovering",
+    "Stairs":                       "IfcStair",
+    "Ramps":                        "IfcRamp",
+    "Railings":                     "IfcRailing",
+    "Curtain Panels":               "IfcCurtainWall",
+    "Curtain Wall Mullions":        "IfcMember",
+    "Doors":                        "IfcDoor",
+    "Windows":                      "IfcWindow",
+    "Furniture":                    "IfcFurnishingElement",
+    "Furniture Systems":            "IfcFurnishingElement",
+    "Casework":                     "IfcFurnishingElement",
+    "Plumbing Fixtures":            "IfcSanitaryTerminal",
+    "Electrical Fixtures":          "IfcElectricAppliance",
+    "Lighting Fixtures":            "IfcLightFixture",
+    "Mechanical Equipment":         "IfcUnitaryEquipment",
+    "Electrical Equipment":         "IfcElectricDistributionBoard",
+    "Structural Foundations":       "IfcFooting",
+    "Foundation Slabs":             "IfcSlab",
+    "Topography":                   "IfcGeographicElement",
+    "Site":                         "IfcSite",
+    "Parking":                      "IfcSpace",
+    "Generic Models":               "IfcBuildingElementProxy",
+    "Mass":                         "IfcBuildingElementProxy",
+    "Specialty Equipment":          "IfcBuildingElementProxy",
+}
+
+
+def classify(obj, category_name: str = "") -> str:
+    """
+    Determine the IFC class for a Speckle object.
+
+    With the new Objects.Data.DataObject:Objects.Data.RevitObject speckle_type,
+    category name is now the primary classification signal.
+
+    Args:
+        obj: A specklepy Base object (leaf element).
+        category_name: The Revit category string from the traversal context
+                       e.g. "Floors", "Walls", "Structural Columns"
+
+    Returns:
+        An IFC class name string e.g. "IfcWall"
+    """
+    speckle_type = getattr(obj, "speckle_type", "") or ""
+
+    # 1. Category name — PRIMARY lookup for RevitObject types
+    if category_name:
+        # Exact match
+        if category_name in CATEGORY_MAP:
+            return CATEGORY_MAP[category_name]
+        # Partial match handles Revit appending IDs e.g. "Structural Framing [12345]"
+        for key, ifc_class in CATEGORY_MAP.items():
+            if key.lower() in category_name.lower():
+                return ifc_class
+
+    # 2. Read 'category' directly off the object itself
+    # Per docs: category is a TOP-LEVEL field on RevitObject, not inside properties
+    obj_category = getattr(obj, "category", None)
+    if obj_category and isinstance(obj_category, str):
+        if obj_category in CATEGORY_MAP:
+            return CATEGORY_MAP[obj_category]
+        for key, ifc_class in CATEGORY_MAP.items():
+            if key.lower() in obj_category.lower():
+                return ifc_class
+
+    # 3. speckle_type — fallback for non-RevitObject types (geometry, structural, etc.)
+    if speckle_type in SPECKLE_TYPE_MAP:
+        return SPECKLE_TYPE_MAP[speckle_type]
+    for key, ifc_class in SPECKLE_TYPE_MAP.items():
+        if speckle_type.startswith(key):
+            return ifc_class
+
+    # 4. Last resort
+    return "IfcBuildingElementProxy"

utils/materials.py

@@ -0,0 +1,151 @@
+# =============================================================================
+# materials.py
+# Reads renderMaterialProxies from the Speckle root object and applies
+# IfcSurfaceStyle colours to IFC geometry.
+#
+# Structure of renderMaterialProxies:
+#   root.renderMaterialProxies = [
+#     {
+#       id: "636259b3..."
+#       value: RenderMaterial {
+#         name:    "Glass"
+#         diffuse: -16744256   ← ARGB packed int (A=255, R=0, G=128, B=192)
+#         opacity: 0.1         ← 0=transparent, 1=opaque
+#       }
+#       objects: ["a1a6b0c2-...", "d5dd3127-...", ...]  ← mesh applicationIds
+#     },
+#     ...
+#   ]
+#
+# Usage:
+#   mgr = MaterialManager(ifc, root)
+#   mgr.apply_to_item(brep_item, mesh_app_id)
+# =============================================================================
+
+import ifcopenshell
+import ifcopenshell.api
+from specklepy.objects.base import Base
+
+
+def _argb_to_rgb(argb_int: int) -> tuple[float, float, float]:
+    """Unpack a signed ARGB int to normalised (R, G, B) floats 0..1."""
+    unsigned = argb_int & 0xFFFFFFFF
+    r = ((unsigned >> 16) & 0xFF) / 255.0
+    g = ((unsigned >> 8)  & 0xFF) / 255.0
+    b = (unsigned         & 0xFF) / 255.0
+    return r, g, b
+
+
+def _get(obj, key, default=None):
+    try:
+        val = getattr(obj, key, None)
+        if val is not None:
+            return val
+    except Exception:
+        pass
+    try:
+        val = obj[key]
+        if val is not None:
+            return val
+    except Exception:
+        pass
+    return default
+
+
+class MaterialManager:
+    """
+    Builds a lookup from mesh applicationId → IfcSurfaceStyle,
+    then applies styles to IFC geometry items.
+    """
+
+    def __init__(self, ifc: ifcopenshell.file, root: Base):
+        self._ifc = ifc
+        # mesh applicationId (lowercase) → IfcSurfaceStyle (populated lazily)
+        self._style_map: dict[str, object] = {}
+        # name → IfcSurfaceStyle (cache to avoid duplicates)
+        self._style_cache: dict[str, object] = {}
+        self._build(root)
+
+    def _build(self, root: Base):
+        """
+        Parse renderMaterialProxies and store raw material data keyed by mesh applicationId.
+        IFC styles are created lazily (only when actually assigned to geometry) to avoid
+        orphaned IfcSurfaceStyle instances that would fail IFC105 validation.
+        """
+        proxies = _get(root, "renderMaterialProxies") or []
+        if not isinstance(proxies, list):
+            proxies = list(proxies) if proxies else []
+
+        # mesh applicationId (lowercase) → (name, diffuse_argb, transparency)
+        self._material_data: dict[str, tuple] = {}
+
+        for proxy in proxies:
+            material = _get(proxy, "value")
+            if material is None:
+                continue
+            name    = _get(material, "name") or "Unnamed"
+            diffuse = _get(material, "diffuse")
+            opacity = _get(material, "opacity")
+            if diffuse is None:
+                continue
+            opacity_val  = float(opacity) if opacity is not None else 1.0
+            transparency = max(0.0, min(1.0, 1.0 - opacity_val))
+
+            objects = _get(proxy, "objects") or []
+            for app_id in (objects if isinstance(objects, list) else []):
+                if app_id:
+                    self._material_data[str(app_id).lower()] = (name, int(diffuse), transparency)
+
+        print(f"   Materials: {len(self._material_data)} mesh mappings (styles created on demand)")
+
+    def _get_or_create_style(self, name: str, diffuse_argb: int, transparency: float):
+        """Return cached style or create a new IfcSurfaceStyle."""
+        cache_key = f"{name}|{diffuse_argb}|{transparency:.4f}"
+        if cache_key in self._style_cache:
+            return self._style_cache[cache_key]
+
+        r, g, b = _argb_to_rgb(diffuse_argb)
+        style = ifcopenshell.api.run("style.add_style", self._ifc, name=name)
+        ifcopenshell.api.run(
+            "style.add_surface_style",
+            self._ifc,
+            style=style,
+            ifc_class="IfcSurfaceStyleRendering",
+            attributes={
+                "SurfaceColour": {"Name": None, "Red": r, "Green": g, "Blue": b},
+                "Transparency": transparency,
+                "ReflectanceMethod": "NOTDEFINED",
+            },
+        )
+        self._style_cache[cache_key] = style
+        return style
+
+    def get_style(self, mesh_app_id: str):
+        """Return the IfcSurfaceStyle for a mesh applicationId (created on demand), or None."""
+        key = str(mesh_app_id).lower()
+        # Return already-created style if cached
+        if key in self._style_map:
+            return self._style_map[key]
+        # Create style now only if this mesh has material data
+        data = self._material_data.get(key)
+        if data is None:
+            return None
+        name, diffuse, transparency = data
+        style = self._get_or_create_style(name, diffuse, transparency)
+        self._style_map[key] = style
+        return style
+
+    def apply_to_item(self, item, mesh_app_id: str):
+        """Assign the material style to a single IFC geometry item (e.g. IfcFacetedBrep)."""
+        style = self.get_style(mesh_app_id)
+        if style is None:
+            return
+        try:
+            ifcopenshell.api.run(
+                "style.assign_item_style",
+                self._ifc,
+                item=item,
+                style=style,
+            )
+        except Exception as e:
+            pass  # Non-fatal — geometry still exports without colour

utils/properties.py

@@ -0,0 +1,177 @@
+# =============================================================================
+# properties.py
+# Extracts Revit data from Speckle DataObjects and writes IFC property sets.
+#
+# Revit parameter structure from the Speckle connector:
+#   obj.properties = {
+#     "elementId": "704282",
+#     "Parameters": {
+#       "Type Parameters": {
+#         "Dimensions": {
+#           "Thickness": {"name": "Thickness", "value": 25.4, "units": "Millimeters", ...}
+#         },
+#         ...
+#       },
+#       "Instance Parameters": {
+#         "Constraints": {
+#           "Level": {"name": "Level", "value": "Level 1", ...}
+#         },
+#         ...
+#       }
+#     }
+#   }
+#
+# We flatten this into two IFC property sets:
+#   Pset_RevitTypeParameters     — from "Type Parameters"
+#   Pset_RevitInstanceParameters — from "Instance Parameters"
+# =============================================================================
+
+import ifcopenshell.api
+from specklepy.objects.base import Base
+
+
+def _safe_val(value) -> str | None:
+    """Convert a value to a clean IFC-safe string."""
+    if value is None:
+        return None
+    if isinstance(value, bool):
+        return "Yes" if value else "No"
+    if isinstance(value, float):
+        # Trim excessive decimals
+        return f"{value:.6g}"
+    if isinstance(value, (int, str)):
+        s = str(value).strip()
+        return s if s else None
+    return str(value).strip() or None
+
+
+def _extract_param(entry) -> tuple[str, str] | None:
+    """
+    Given a Revit parameter entry dict like:
+      {"name": "Thickness", "value": 25.4, "units": "Millimeters", ...}
+    Returns (display_name, display_value) or None if unusable.
+    """
+    if not isinstance(entry, dict):
+        return None
+    name = entry.get("name")
+    value = entry.get("value")
+    if not name or value is None:
+        return None
+    units = entry.get("units", "")
+    # Skip non-informative unit labels
+    skip_units = {"", "None", "General", "Currency", "Integer"}
+    val_str = _safe_val(value)
+    if val_str is None:
+        return None
+    if units and units not in skip_units:
+        display = f"{val_str} {units}"
+    else:
+        display = val_str
+    return str(name), display
+
+
+def _flatten_param_group(group: dict) -> dict:
+    """
+    Flatten one parameter group (e.g. "Dimensions", "Constraints") dict.
+    Each value is a Revit parameter entry {"name":..., "value":..., "units":...}.
+    Returns {display_name: display_value}.
+    """
+    result = {}
+    if not isinstance(group, dict):
+        return result
+    for _internal_key, entry in group.items():
+        pair = _extract_param(entry)
+        if pair:
+            name, val = pair
+            result[name] = val
+    return result
+
+
+def _extract_parameter_block(params_block: dict) -> dict:
+    """
+    Flatten all groups in a parameter block (Type Parameters or Instance Parameters).
+    Returns a merged {display_name: display_value} dict.
+    """
+    result = {}
+    if not isinstance(params_block, dict):
+        return result
+    for _group_name, group in params_block.items():
+        result.update(_flatten_param_group(group))
+    return result
+
+
+def _get_properties_dict(obj: Base) -> dict:
+    """Extract the raw properties dict from a DataObject."""
+    for key in ["properties", "@properties", "_properties"]:
+        try:
+            props = obj[key]
+            if props is None:
+                continue
+            if hasattr(props, "get_dynamic_member_names"):
+                names = props.get_dynamic_member_names()
+                return {n: props[n] for n in names}
+            if isinstance(props, dict):
+                return props
+        except Exception:
+            continue
+    return {}
+
+
+def _write_pset(ifc, element, pset_name: str, props: dict):
+    """Write a property set if there are any properties."""
+    if not props:
+        return
+    try:
+        pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name=pset_name)
+        ifcopenshell.api.run("pset.edit_pset", ifc, pset=pset, properties=props)
+    except Exception as e:
+        print(f"  ⚠️  {pset_name}: {e}")
+
+
+def write_properties(ifc, element, obj: Base):
+    """
+    Write Revit parameters as IFC property sets.
+    Creates separate psets for Type and Instance parameters.
+    """
+    props_dict = _get_properties_dict(obj)
+    parameters = props_dict.get("Parameters") or {}
+
+    # Type Parameters → Pset_RevitTypeParameters
+    type_params = parameters.get("Type Parameters") or {}
+    type_flat = _extract_parameter_block(type_params)
+    _write_pset(ifc, element, "RVT_TypeParameters", type_flat)
+
+    # Instance Parameters → Pset_RevitInstanceParameters
+    inst_params = parameters.get("Instance Parameters") or {}
+    inst_flat = _extract_parameter_block(inst_params)
+    _write_pset(ifc, element, "RVT_InstanceParameters", inst_flat)
+
+    # Top-level semantic fields → Pset_RevitIdentity
+    identity = {}
+    for field in ["type", "family", "category", "level"]:
+        val = getattr(obj, field, None)
+        if val and isinstance(val, str) and val.strip():
+            identity[field.capitalize()] = val.strip()
+    # Also include elementId if present
+    elem_id = props_dict.get("elementId")
+    if elem_id:
+        identity["ElementId"] = str(elem_id)
+
+    _write_pset(ifc, element, "RVT_Identity", identity)
+
+
+def write_common_properties(ifc, element, obj: Base, category_name: str = ""):
+    """
+    Write Pset_SpeckleData for traceability back to the Speckle source object.
+    """
+    props = {}
+    speckle_id   = getattr(obj, "id", None)
+    app_id       = getattr(obj, "applicationId", None)
+    speckle_type = getattr(obj, "speckle_type", None)
+
+    if speckle_id:   props["SpeckleId"]      = str(speckle_id)
+    if app_id:       props["ApplicationId"]  = str(app_id)
+    if speckle_type: props["SpeckleType"]    = str(speckle_type)
+    if category_name: props["RevitCategory"] = str(category_name)
+
+    _write_pset(ifc, element, "RVT_SpeckleData", props)

utils/receiver.py

@@ -0,0 +1,68 @@
+# =============================================================================
+# receiver.py
+# Connects to Speckle and receives the root Base object for a given version.
+# =============================================================================
+
+from specklepy.api.client import SpeckleClient
+from specklepy.api.credentials import get_default_account
+from specklepy.api import operations
+from specklepy.transports.server import ServerTransport
+import utils.config as config
+
+
+def get_client() -> SpeckleClient:
+    """
+    Create and authenticate a SpeckleClient.
+    Uses a personal access token from config.py.
+    To use your local Speckle Manager account instead, swap to get_default_account().
+    """
+    client = SpeckleClient(host=config.SPECKLE_HOST)
+
+    if config.SPECKLE_TOKEN and config.SPECKLE_TOKEN != "YOUR_PERSONAL_ACCESS_TOKEN":
+        client.authenticate_with_token(config.SPECKLE_TOKEN)
+    else:
+        # Fallback: use account from Speckle Manager desktop app
+        account = get_default_account()
+        if account is None:
+            raise RuntimeError(
+                "No Speckle account found. Either set SPECKLE_TOKEN in config.py "
+                "or log in via Speckle Manager."
+            )
+        client.authenticate_with_account(account)
+
+    return client
+
+
+def receive_version(project_id: str, version_id: str):
+    """
+    Receive the root Base object from a Speckle version.
+
+    Args:
+        project_id: The Speckle project (stream) ID.
+        version_id: The version (commit) ID to receive.
+
+    Returns:
+        A specklepy Base object — the root of the object graph.
+    """
+    client = get_client()
+
+    print(f"🔗 Connecting to {config.SPECKLE_HOST}...")
+    print(f"📦 Receiving project={project_id}  version={version_id}")
+
+    # Get version metadata to find the referenced object ID
+    version = client.version.get(version_id,project_id)
+    referenced_object_id = version.referenced_object
+
+    # Download the full object graph
+    transport = ServerTransport(stream_id=project_id, client=client)
+    base = operations.receive(referenced_object_id, transport)
+
+    # Read units from the root object
+    units = getattr(base, "units", config.DEFAULT_UNITS) or config.DEFAULT_UNITS
+
+    # IFC file is declared in MILLIMETRES — no conversion needed.
+    # All geometry stays in source units (mm). scale=1.0 means "keep as-is".
+    scale = 1.0
+
+    print(f"✅ Received root object  units={units}  scale=1.0 (IFC declared as mm)")
+    return base, scale

utils/traversal.py

@@ -0,0 +1,246 @@
+# =============================================================================
+# traversal.py
+# Walks the nested Speckle Collection tree from a Revit export.
+#
+# Expected structure (from your screenshot):
+#   root
+#   └── elements[]
+#       └── Collection (project)
+#           └── elements[]
+#               └── Collection (Level 18, Level 19, ...)   ← storeys
+#                   └── elements[]
+#                       └── Collection (Floors, Walls, ...)  ← categories
+#                           └── elements[]
+#                               └── Base object             ← real BIM element
+# =============================================================================
+
+from typing import Generator, Tuple
+from specklepy.objects.base import Base
+
+
+# --------------------------------------------------------------------------- #
+# Low-level helpers
+# --------------------------------------------------------------------------- #
+
+def is_collection(obj) -> bool:
+    """Returns True if this object is a Speckle Collection node (not a leaf element)."""
+    speckle_type = getattr(obj, "speckle_type", "") or ""
+    return "Collection" in speckle_type
+
+
+def get_children(obj) -> list:
+    """
+    Safely get the 'elements' list from a Base/Collection object.
+    Handles both 'elements' and '@elements' (detached) variants.
+    """
+    for key in ["elements", "@elements"]:
+        try:
+            val = obj[key]
+            if val is not None:
+                return list(val)
+        except Exception:
+            continue
+    return []
+
+
+def get_prop(obj, key: str, default=None):
+    """Safe property access for Speckle Base objects — avoids AttributeError."""
+    try:
+        val = getattr(obj, key, None)
+        if val is None:
+            val = obj[key]
+        return val
+    except Exception:
+        return default
+
+
+# speckle_type fragments that mark a non-exportable / spatial-structure object
+_SKIP_TYPE_FRAGMENTS = {
+    "Collection", "Level", "Grid", "View", "RenderMaterial",
+    "Site", "Building", "Storey",
+}
+
+
+def _is_valid_element(obj) -> bool:
+    """
+    Returns True only for leaf objects that should become IFC elements.
+    Filters out Collections, spatial structure types, and other non-geometry nodes.
+    """
+    if obj is None:
+        return False
+
+    speckle_type = getattr(obj, "speckle_type", "") or ""
+
+    for fragment in _SKIP_TYPE_FRAGMENTS:
+        if fragment in speckle_type:
+            return False
+
+    return True
+
+
+# --------------------------------------------------------------------------- #
+# Helpers
+# --------------------------------------------------------------------------- #
+
+def _element_level(obj) -> str:
+    """
+    Try to read the level/storey name directly from an element's properties.
+    Handles both flat and deeply nested Revit property structures.
+    """
+    # Top-level field (Revit connector puts it here for parent elements)
+    level = get_prop(obj, "level") or get_prop(obj, "Level")
+    if level and isinstance(level, str) and level.strip():
+        return level.strip()
+
+    props = get_prop(obj, "properties")
+    if isinstance(props, dict):
+        # Flat key
+        for key in ["Level", "level", "Building Storey"]:
+            val = props.get(key)
+            if val and isinstance(val, str) and val.strip():
+                return val.strip()
+
+        # Nested: properties.Instance Parameters.Constraints.Level.value
+        # (used by curtain wall children / panels / mullions)
+        instance_params = props.get("Instance Parameters") or {}
+        constraints = instance_params.get("Constraints") or {}
+        level_entry = constraints.get("Level") or {}
+        if isinstance(level_entry, dict):
+            val = level_entry.get("value")
+            if val and isinstance(val, str) and val.strip():
+                return val.strip()
+
+        # Also check Identity Data
+        identity = props.get("Identity Data") or {}
+        for key in ["Level", "level"]:
+            val = identity.get(key)
+            if val and isinstance(val, str) and val.strip():
+                return val.strip()
+
+    return ""
+
+
+def _yield_element_and_children(obj, level_name: str, category_name: str):
+    """
+    Yield a leaf element, then recursively yield any DataObject children
+    from its elements[] list (e.g. curtain wall panels and mullions).
+    Children have their own level and displayValue geometry.
+    """
+    yield obj, level_name, category_name
+
+    children = get_children(obj)
+    for child in children:
+        if child is None or is_collection(child):
+            continue
+        if not _is_valid_element(child):
+            continue
+        # Get child's own level, fall back to parent's level
+        child_level = _element_level(child) or level_name
+        if child_level and child_level != "Unknown Level":
+            child_category = getattr(child, "category", None) or category_name
+            yield from _yield_element_and_children(child, child_level, child_category)
+
+
+# --------------------------------------------------------------------------- #
+# Main traversal
+# --------------------------------------------------------------------------- #
+
+def traverse(
+    root: Base,
+) -> Generator[Tuple[Base, str, str], None, None]:
+    """
+    Walk the full Speckle object tree from the root Base object.
+
+    Yields:
+        (element, level_name, category_name) for every leaf BIM element found.
+        level_name   — e.g. "Level 18"
+        category_name — e.g. "Floors", "Walls", "Structural Columns"
+    """
+    root_children = get_children(root)
+
+    if not root_children:
+        if _is_valid_element(root):
+            yield root, "Unknown Level", "Unknown Category"
+        return
+
+    for child in root_children:
+        if is_collection(child):
+            yield from _walk_level(child)
+        else:
+            if _is_valid_element(child):
+                level = _element_level(child)
+                if level:
+                    yield child, level, "Unknown Category"
+
+
+def _walk_level(project_collection: Base):
+    """Walk the project collection → level collections."""
+    for level_obj in get_children(project_collection):
+        level_name = getattr(level_obj, "name", None) or ""
+
+        if is_collection(level_obj):
+            # Only walk into this level if it has a real name
+            if level_name and level_name != "Unknown Level":
+                yield from _walk_category(level_obj, level_name)
+        else:
+            if _is_valid_element(level_obj):
+                level = _element_level(level_obj) or level_name
+                if level and level != "Unknown Level":
+                    yield from _yield_element_and_children(level_obj, level, "Unknown Category")
+
+
+def _walk_category(level_obj: Base, level_name: str):
+    """Walk level collection → category collections → leaf elements."""
+    for category_obj in get_children(level_obj):
+        category_name = getattr(category_obj, "name", "Unknown Category") or "Unknown Category"
+
+        if is_collection(category_obj):
+            for element in get_children(category_obj):
+                if is_collection(element):
+                    # One extra nesting level (e.g. sub-families)
+                    for sub_element in get_children(element):
+                        if _is_valid_element(sub_element):
+                            level = _element_level(sub_element) or level_name
+                            if level and level != "Unknown Level":
+                                yield from _yield_element_and_children(sub_element, level, category_name)
+                else:
+                    if _is_valid_element(element):
+                        level = _element_level(element) or level_name
+                        if level and level != "Unknown Level":
+                            yield from _yield_element_and_children(element, level, category_name)
+        else:
+            if _is_valid_element(category_obj):
+                level = _element_level(category_obj) or level_name
+                if level and level != "Unknown Level":
+                    yield from _yield_element_and_children(category_obj, level, "Unknown Category")
+
+
+# --------------------------------------------------------------------------- #
+# Debug helper
+# --------------------------------------------------------------------------- #
+
+def print_tree(obj: Base, indent: int = 0, max_depth: int = 5):
+    """
+    Print the object tree structure for debugging.
+    Call this on the root object to understand your data before exporting.
+
+    Usage:
+        from traversal import print_tree
+        print_tree(base)
+    """
+    if indent > max_depth:
+        return
+
+    prefix = "  " * indent
+    name = getattr(obj, "name", None) or ""
+    speckle_type = getattr(obj, "speckle_type", "") or ""
+    children = get_children(obj)
+    child_count = f"  ({len(children)} children)" if children else ""
+
+    print(f"{prefix}├─ [{speckle_type}]  name={name!r}{child_count}")
+
+    for child in children[:5]:  # limit to first 5 per level to avoid spam
+        print_tree(child, indent + 1, max_depth)
+
+    if len(children) > 5:
+        print(f"{prefix}   ... and {len(children) - 5} more")

utils/writer.py

@@ -0,0 +1,115 @@
+# =============================================================================
+# writer.py
+# Creates and manages the IFC file structure:
+#   IfcProject → IfcSite → IfcBuilding → IfcBuildingStorey (one per level)
+#
+# Also provides StoreyManager which lazily creates storeys on demand
+# as the traversal encounters new level names.
+# =============================================================================
+
+import ifcopenshell
+import ifcopenshell.api
+import utils.config as config
+
+
+def create_ifc_scaffold() -> tuple:
+    """
+    Create the IFC file with the required project/site/building hierarchy.
+
+    Returns:
+        (ifc_file, building, body_context)
+        - ifc_file:     The ifcopenshell file object
+        - building:     The IfcBuilding entity (storeys are assigned under this)
+        - body_context: The Body geometry subcontext for shape representations
+    """
+    ifc = ifcopenshell.file(schema="IFC4X3")
+
+    # Project
+    project = ifcopenshell.api.run(
+        "root.create_entity", ifc,
+        ifc_class="IfcProject",
+        name=config.IFC_PROJECT_NAME,
+    )
+
+    # Units — millimetres (matching Revit/Speckle source data)
+    # This avoids any mm→m conversion errors and keeps coordinates at full precision
+    ifcopenshell.api.run(
+        "unit.assign_unit", ifc,
+        length={"is_metric": True, "raw": "MILLIMETRES"},
+    )
+
+    # Geometry contexts
+    model_ctx = ifcopenshell.api.run(
+        "context.add_context", ifc,
+        context_type="Model",
+    )
+    body_ctx = ifcopenshell.api.run(
+        "context.add_context", ifc,
+        context_type="Model",
+        context_identifier="Body",
+        target_view="MODEL_VIEW",
+        parent=model_ctx,
+    )
+
+    # Spatial hierarchy
+    site = ifcopenshell.api.run(
+        "root.create_entity", ifc,
+        ifc_class="IfcSite",
+        name=config.IFC_SITE_NAME,
+    )
+    building = ifcopenshell.api.run(
+        "root.create_entity", ifc,
+        ifc_class="IfcBuilding",
+        name=config.IFC_BUILDING_NAME,
+    )
+
+    ifcopenshell.api.run(
+        "aggregate.assign_object", ifc,
+        relating_object=project,
+        products=[site],
+    )
+    ifcopenshell.api.run(
+        "aggregate.assign_object", ifc,
+        relating_object=site,
+        products=[building],
+    )
+
+    return ifc, building, body_ctx
+
+
+class StoreyManager:
+    """
+    Lazily creates IfcBuildingStorey entities as new level names are encountered.
+    Keeps storeys in insertion order so the IFC file is logically ordered.
+    """
+
+    def __init__(self, ifc: ifcopenshell.file, building):
+        self.ifc = ifc
+        self.building = building
+        self._storeys: dict[str, object] = {}  # level_name → IfcBuildingStorey
+
+    def get_or_create(self, level_name: str):
+        """Return existing storey or create a new one for this level name."""
+        if level_name not in self._storeys:
+            storey = ifcopenshell.api.run(
+                "root.create_entity", self.ifc,
+                ifc_class="IfcBuildingStorey",
+                name=level_name,
+            )
+            ifcopenshell.api.run(
+                "aggregate.assign_object", self.ifc,
+                relating_object=self.building,
+                products=[storey],
+            )
+            self._storeys[level_name] = storey
+            print(f"  🏢 Created storey: {level_name}")
+
+        return self._storeys[level_name]
+
+    @property
+    def count(self) -> int:
+        return len(self._storeys)
+
+    @property
+    def names(self) -> list[str]:
+        return list(self._storeys.keys())