Hide MEP gizmos on non-parametric elements

MEP elements imported as tessellation / brep (no IfcExtrudedAreaSolid
or IfcSweptDiskSolid in their body representation) can't be
parametrically edited — the gizmos offer affordances the geometry
kernel has no path to honour. tool.System.has_parametric_body
inspects the Model/Body/MODEL_VIEW representation and returns True
only when at least one item resolves to one of the two
profile-sweep primitives.

The gate is wired into:
- GizmoMEPActions.is_eligible_object (the action icon group)
- _active_is_flow_segment / _active_is_bend_fitting visibility
  predicates the icon row consults per-icon
- GizmoPipeSegmentEdition / GizmoDuctSegmentEdition is_element_type

tool.Parametric.is_pipe_segment / is_duct_segment stay IFC-class-only
so their truth-table contract test keeps reading a single concern.

Generated with the assistance of an AI coding tool.

src/bonsai/bonsai/bim/module/model/mep.py

@@ -2619,7 +2619,7 @@ class GizmoPipeSegmentEdition(bpy.types.GizmoGroup, _MEPSegmentEditionMixin, giz
 
     @classmethod
     def is_element_type(cls, element):
-        return tool.Parametric.is_pipe_segment(element)
+        return tool.Parametric.is_pipe_segment(element) and tool.System.has_parametric_body(element)
 
 
 class GizmoDuctSegmentEdition(bpy.types.GizmoGroup, _MEPSegmentEditionMixin, gizmo.BaseParametricGizmoGroup):
@@ -2646,7 +2646,7 @@ class GizmoDuctSegmentEdition(bpy.types.GizmoGroup, _MEPSegmentEditionMixin, giz
 
     @classmethod
     def is_element_type(cls, element):
-        return tool.Parametric.is_duct_segment(element)
+        return tool.Parametric.is_duct_segment(element) and tool.System.has_parametric_body(element)
 
 
 # --- GizmoMEPActions group + visibility helpers ----------------------------
@@ -2658,9 +2658,9 @@ def _selection_size() -> int:
 
 def _active_is_flow_segment(obj: bpy.types.Object) -> bool:
     element = tool.Ifc.get_entity(obj)
-    if element is None:
+    if element is None or not element.is_a("IfcFlowSegment"):
         return False
-    return element.is_a("IfcFlowSegment")
+    return tool.System.has_parametric_body(element)
 
 
 def _active_mep_has_connected_neighbor(obj: bpy.types.Object) -> bool:
@@ -2677,7 +2677,10 @@ def _active_mep_has_connected_neighbor(obj: bpy.types.Object) -> bool:
 
 
 def _active_is_bend_fitting(obj: bpy.types.Object) -> bool:
-    return _is_bend_fitting(tool.Ifc.get_entity(obj))
+    element = tool.Ifc.get_entity(obj)
+    if not _is_bend_fitting(element):
+        return False
+    return tool.System.has_parametric_body(element)
 
 
 class GizmoMEPActions(bpy.types.GizmoGroup, gizmo.BaseIconActionGroup):
@@ -2789,9 +2792,9 @@ class GizmoMEPActions(bpy.types.GizmoGroup, gizmo.BaseIconActionGroup):
         if bend_props is not None and bend_props.is_active:
             return False
         element = tool.Ifc.get_entity(obj)
-        if element is None:
+        if element is None or not tool.System.is_mep_element(element):
             return False
-        return tool.System.is_mep_element(element)
+        return tool.System.has_parametric_body(element)
 
     def setup(self, context: bpy.types.Context) -> None:
         super().setup(context)

src/bonsai/bonsai/tool/system.py

@@ -488,6 +488,24 @@ class System(bonsai.core.tool.System):
     def is_mep_element(cls, element: ifcopenshell.entity_instance) -> bool:
         return element.is_a("IfcFlowSegment") or element.is_a("IfcFlowFitting")
 
+    @classmethod
+    def has_parametric_body(cls, element: ifcopenshell.entity_instance) -> bool:
+        """True when the MEP element's body representation is a profile sweep
+        (``IfcExtrudedAreaSolid`` for segments, ``IfcSweptDiskSolid`` for
+        fittings) — the shape the parametric edit + MEP action gizmos can
+        actually mutate. Tessellation- or brep-imported MEP elements return
+        False so their gizmos hide rather than offer edits the geometry
+        kernel can't honour."""
+        import bonsai.tool as tool
+
+        body = tool.Geometry.get_body_representation(element)
+        if body is None:
+            return False
+        for item in tool.Ifc.get().traverse(body):
+            if item.is_a("IfcExtrudedAreaSolid") or item.is_a("IfcSweptDiskSolid"):
+                return True
+        return False
+
     @classmethod
     def walk_connected_mep_elements(
         cls, start_element: ifcopenshell.entity_instance

src/bonsai/test/bim/module/model/test_mep_actions_visibility.py

@@ -214,7 +214,9 @@ def test_active_is_flow_segment_handles_unbound_object():
 
 def test_active_is_flow_segment_classifies_segment_vs_fitting():
     """Only IfcFlowSegment lights the lock-icon row; IfcFlowFitting (the
-    bend's own class) does not."""
+    bend's own class) does not. The parametric-body gate is mocked True
+    here — its dedicated truth-table is in test_mep_actions_visibility
+    sibling tests."""
     from bonsai.bim.module.model.mep import _active_is_flow_segment
 
     segment_elem = Mock()
@@ -223,10 +225,11 @@ def test_active_is_flow_segment_classifies_segment_vs_fitting():
     fitting_elem.is_a = lambda c: c == "IfcFlowFitting"
 
     plain = Mock()
-    with patch("bonsai.bim.module.model.mep.tool.Ifc.get_entity", return_value=segment_elem):
-        assert _active_is_flow_segment(plain) is True
-    with patch("bonsai.bim.module.model.mep.tool.Ifc.get_entity", return_value=fitting_elem):
-        assert _active_is_flow_segment(plain) is False
+    with patch("bonsai.bim.module.model.mep.tool.System.has_parametric_body", return_value=True):
+        with patch("bonsai.bim.module.model.mep.tool.Ifc.get_entity", return_value=segment_elem):
+            assert _active_is_flow_segment(plain) is True
+        with patch("bonsai.bim.module.model.mep.tool.Ifc.get_entity", return_value=fitting_elem):
+            assert _active_is_flow_segment(plain) is False
 
 
 def test_active_mep_has_connected_neighbor_returns_false_on_no_entity():

src/bonsai/test/bim/module/model/test_mep_segment_edition.py

@@ -170,11 +170,12 @@ def test_gizmo_group_class_wiring(gizmo_cls_name, bl_idname, is_element_predicat
 
     cls = getattr(mep, gizmo_cls_name)
     assert cls.bl_idname == bl_idname
-    # The element_type predicate must delegate to the matching tool.Parametric.is_*.
     predicate = getattr(tool.Parametric, is_element_predicate)
     fake_element = Mock()
     fake_element.is_a.return_value = True
-    with patch.object(tool.Parametric, is_element_predicate, side_effect=predicate) as p:
+    with patch.object(tool.Parametric, is_element_predicate, side_effect=predicate) as p, patch.object(
+        tool.System, "has_parametric_body", return_value=True
+    ):
         cls.is_element_type(fake_element)
     assert p.called, f"{gizmo_cls_name}.is_element_type did not delegate to Parametric.{is_element_predicate}"