diff --git a/src/bonsai/bonsai/tool/model.py b/src/bonsai/bonsai/tool/model.py
index f54633c3cc..0b9821dae5 100644
--- a/src/bonsai/bonsai/tool/model.py
+++ b/src/bonsai/bonsai/tool/model.py
@@ -24,7 +24,7 @@ import collections.abc
 import json
 from collections.abc import Callable, Iterable, Sequence
 from copy import deepcopy
-from math import atan, cos, degrees, pi, radians
+from math import atan, atan2, cos, degrees, pi, radians, sin
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -660,6 +660,50 @@ class Model(bonsai.core.tool.Model):
             )
             cls.circles.append([offset, offset + 1])
             cls.edges.append((offset, offset + 1))
+        elif curve.is_a("IfcTrimmedCurve"):
+            # A trimmed circular arc, e.g. a fillet segment inside an IfcCompositeCurve
+            # exported by Revit. Reconstruct it as a 3-point (start, mid, end) arc so it
+            # round-trips through the IFCARCINDEX vertex group like IfcArcIndex segments do.
+            basis_curve = curve.BasisCurve
+            if not basis_curve.is_a("IfcCircle"):
+                raise cls.UnsupportedCurveForConversion(f"Profile has unsupported curve type: {curve}.")
+            circle_position = Matrix(ifcopenshell.util.placement.get_axis2placement(basis_curve.Position).tolist())
+            circle_position.translation *= cls.unit_scale
+            radius = cls.convert_unit_to_si(basis_curve.Radius)
+            # Trim parameters on a circle are angles expressed in the project plane angle unit.
+            angle_scale = ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get(), "PLANEANGLEUNIT")
+
+            def _trim_angle(trim: tuple[ifcopenshell.entity_instance, ...]) -> Union[float, None]:
+                # Prefer a parameter (angle) trim, else derive the angle from a cartesian point.
+                for select in trim:
+                    if select.is_a("IfcParameterValue"):
+                        return float(select.wrappedValue) * angle_scale
+                for select in trim:
+                    if select.is_a("IfcCartesianPoint"):
+                        local = circle_position.inverted() @ Vector(cls.convert_unit_to_si(select.Coordinates)).to_3d()
+                        return atan2(local.y, local.x)
+                return None
+
+            angle_1 = _trim_angle(curve.Trim1)
+            angle_2 = _trim_angle(curve.Trim2)
+            if angle_1 is None or angle_2 is None:
+                raise cls.UnsupportedCurveForConversion(f"Profile has unsupported curve type: {curve}.")
+            # SenseAgreement tells us whether the arc runs with (CCW) or against (CW) the
+            # basis curve direction; unwrap the end angle accordingly so the midpoint lands
+            # on the actual swept arc rather than its complement.
+            if curve.SenseAgreement:
+                while angle_2 < angle_1:
+                    angle_2 += 2 * pi
+            else:
+                while angle_2 > angle_1:
+                    angle_2 -= 2 * pi
+            angle_mid = (angle_1 + angle_2) / 2
+            for angle in (angle_1, angle_mid, angle_2):
+                local_point = Vector((radius * cos(angle), radius * sin(angle), 0.0))
+                cls.vertices.append(position @ circle_position @ local_point)
+            cls.arcs.append([offset, offset + 1, offset + 2])
+            cls.edges.append((offset, offset + 1))
+            cls.edges.append((offset + 1, offset + 2))
         else:
             raise cls.UnsupportedCurveForConversion(f"Profile has unsupported curve type: {curve}.")