Simple support for API listeners for parametric IFC authoring - editing any parameter can now trigger events from a "parametric engine" which synchronises other related geometry and attributes in the IFC dataset. Implement auto box generation as a first demo.

src/blenderbim/blenderbim/bim/__init__.py

@@ -10,6 +10,7 @@ if bpy is not None:
 
     modules = {
         "project": None,
+        "parametric": None,
         "search": None,
         "bcf": None,
         "root": None,

src/blenderbim/blenderbim/bim/module/geometry/operator.py

@@ -14,14 +14,6 @@ from ifcopenshell.api.void.data import Data as VoidData
 from mathutils import Vector
 
 
-def get_context_id(context_type, context_identifier, target_view):
-    for context in ContextData.contexts.values():
-        if context["ContextType"] == context_type:
-            for i, subcontext in context["HasSubContexts"].items():
-                if subcontext["ContextIdentifier"] == context_identifier and subcontext["TargetView"] == target_view:
-                    return i
-
-
 class EditObjectPlacement(bpy.types.Operator):
     bl_idname = "bim.edit_object_placement"
     bl_label = "Edit Object Placement"
@@ -107,23 +99,6 @@ class AddRepresentation(bpy.types.Operator):
             print("Failed to write shape representation")
             return {"FINISHED"}
 
-        # TODO: Migrate to parametric engine system
-        box_context_id = get_context_id("Model", "Box", "MODEL_VIEW")
-        old_box = ifcopenshell.util.representation.get_representation(product, "Model", "Box", "MODEL_VIEW")
-        if (
-            box_context_id
-            and context_of_items.ContextType == "Model"
-            and context_of_items.ContextIdentifier
-            and context_of_items.ContextIdentifier == "Body"
-        ):
-            if old_box:
-                bpy.ops.bim.remove_representation(representation_id=old_box.id(), obj=obj.name)
-            representation_data["context"] = self.file.by_id(box_context_id)
-            new_box = ifcopenshell.api.run("geometry.add_representation", self.file, **representation_data)
-            ifcopenshell.api.run(
-                "geometry.assign_representation", self.file, **{"product": product, "representation": new_box}
-            )
-
         [
             bpy.ops.bim.add_style(material=s.material.name)
             for s in obj.material_slots
@@ -326,20 +301,6 @@ class UpdateRepresentation(bpy.types.Operator):
 
         new_representation = ifcopenshell.api.run("geometry.add_representation", self.file, **representation_data)
 
-        box_context_id = get_context_id("Model", "Box", "MODEL_VIEW")
-        old_box = ifcopenshell.util.representation.get_representation(product, "Model", "Box", "MODEL_VIEW")
-        if (
-            box_context_id
-            and old_box
-            and context_of_items.ContextType == "Model"
-            and context_of_items.ContextIdentifier
-            and context_of_items.ContextIdentifier == "Body"
-        ):
-            representation_data["context"] = self.file.by_id(box_context_id)
-            new_box = ifcopenshell.api.run("geometry.add_representation", self.file, **representation_data)
-            for inverse in self.file.get_inverse(old_box):
-                ifcopenshell.util.element.replace_attribute(inverse, old_box, new_box)
-
         ifcopenshell.api.run(
             "geometry.assign_styles",
             self.file,

src/blenderbim/blenderbim/bim/module/parametric/__init__.py

@@ -0,0 +1,15 @@
+import bpy
+from . import ui, operator
+
+classes = (
+    operator.ActivateParametricEngine,
+    ui.BIM_PT_parametric,
+)
+
+
+def register():
+    pass
+
+
+def unregister():
+    pass

src/blenderbim/blenderbim/bim/module/parametric/operator.py

@@ -0,0 +1,38 @@
+import bpy
+import ifcopenshell
+import ifcopenshell.api
+import ifcopenshell.util.representation
+from blenderbim.bim.ifc import IfcStore
+
+
+def generate_box(usecase_path, ifc_file, **settings):
+    box_context = ifcopenshell.util.representation.get_context(ifc_file, "Model", "Box", "MODEL_VIEW")
+    if not box_context:
+        return
+    obj = settings["blender_object"]
+    product = ifc_file.by_id(obj.BIMObjectProperties.ifc_definition_id)
+    old_box = ifcopenshell.util.representation.get_representation(product, "Model", "Box", "MODEL_VIEW")
+    if settings["context"].ContextType == "Model" and getattr(settings["context"], "ContextIdentifier") == "Body":
+        if old_box:
+            bpy.ops.bim.remove_representation(representation_id=old_box.id(), obj=obj.name)
+
+        new_settings = settings.copy()
+        new_settings["context"] = box_context
+        new_box = ifcopenshell.api.run(
+            "geometry.add_representation", ifc_file, should_run_listeners=False, **new_settings
+        )
+        ifcopenshell.api.run(
+            "geometry.assign_representation",
+            ifc_file,
+            should_run_listeners=False,
+            **{"product": product, "representation": new_box}
+        )
+
+
+class ActivateParametricEngine(bpy.types.Operator):
+    bl_idname = "bim.activate_parametric_engine"
+    bl_label = "Activate Parametric Engine"
+
+    def execute(self, context):
+        ifcopenshell.api.add_post_listener("geometry.add_representation", IfcStore.get_file(), generate_box)
+        return {"FINISHED"}

src/blenderbim/blenderbim/bim/module/parametric/ui.py

@@ -0,0 +1,22 @@
+from bpy.types import Panel
+from blenderbim.bim.ifc import IfcStore
+from ifcopenshell.api.type.data import Data
+
+
+class BIM_PT_parametric(Panel):
+    bl_label = "IFC Parametric Engines"
+    bl_idname = "BIM_PT_parametric"
+    bl_options = {"DEFAULT_CLOSED"}
+    bl_space_type = "PROPERTIES"
+    bl_region_type = "WINDOW"
+    bl_context = "scene"
+
+    @classmethod
+    def poll(cls, context):
+        return IfcStore.get_file()
+
+    def draw(self, context):
+        #props = context.active_object.BIMTypeProperties
+        row = self.layout.row(align=True)
+        #row.prop(props, "relating_type_class", text="")
+        row.operator("bim.activate_parametric_engine", icon="PLUGIN")

src/ifcopenshell-python/ifcopenshell/api/__init__.py

@@ -1,11 +1,38 @@
 import importlib
+import ifcopenshell
 import ifcopenshell.api
 
 
-def run(usecase_path, ifc_file=None, **settings):
+registered_ifcs = {}
+pre_listeners = {}
+post_listeners = {}
+
+
+def run(usecase_path, ifc_file=None, should_run_listeners=True, **settings):
+    ifc_key = registered_ifcs.setdefault(ifc_file, ifcopenshell.guid.new())
+
+    if should_run_listeners:
+        for listener in pre_listeners.get(".".join([ifc_key, usecase_path]), []):
+            listener(usecase_path, ifc_file, **settings)
     importlib.import_module(f"ifcopenshell.api.{usecase_path}")
     module, usecase = usecase_path.split(".")
     usecase_class = getattr(getattr(getattr(ifcopenshell.api, module), usecase), "Usecase")
+
     if ifc_file:
-        return usecase_class(ifc_file, **settings).execute()
+        result = usecase_class(ifc_file, **settings).execute()
-    return usecase_class(**settings).execute()
+    else:
+        result = usecase_class(**settings).execute()
+
+    if should_run_listeners:
+        for listener in post_listeners.get(".".join([ifc_key, usecase_path]), []):
+            listener(usecase_path, ifc_file, **settings)
+    return result
+
+
+def add_pre_listener(usecase_path, ifc_file, callback):
+    ifc_key = registered_ifcs.setdefault(ifc_file, ifcopenshell.guid.new())
+    pre_listeners.setdefault(".".join([ifc_key, usecase_path]), set()).add(callback)
+
+def add_post_listener(usecase_path, ifc_file, callback):
+    ifc_key = registered_ifcs.setdefault(ifc_file, ifcopenshell.guid.new())
+    post_listeners.setdefault(".".join([ifc_key, usecase_path]), set()).add(callback)