diff --git a/raillabel/format/seg3d.py b/raillabel/format/seg3d.py
index 76ef176..31dd7c0 100644
--- a/raillabel/format/seg3d.py
+++ b/raillabel/format/seg3d.py
@@ -8,7 +8,7 @@
 
 from raillabel.json_format import JSONVec
 
-from ._attributes import _attributes_from_json
+from ._attributes import _attributes_from_json, _attributes_to_json
 
 
 @dataclass
@@ -37,6 +37,16 @@ def from_json(cls, json: JSONVec, object_id: UUID) -> Seg3d:
             attributes=_attributes_from_json(json.attributes),
         )
 
+    def to_json(self, uid: UUID, object_type: str) -> JSONVec:
+        """Export this object into the RailLabel JSON format."""
+        return JSONVec(
+            name=self.name(object_type),
+            val=self.point_ids,
+            coordinate_system=self.sensor_id,
+            uid=uid,
+            attributes=_attributes_to_json(self.attributes),
+        )
+
     def name(self, object_type: str) -> str:
         """Return the name of the annotation used for indexing in the object data pointers."""
         return f"{self.sensor_id}__vec__{object_type}"
diff --git a/tests/test_raillabel/format/test_seg3d.py b/tests/test_raillabel/format/test_seg3d.py
index 0dd2716..a290aa6 100644
--- a/tests/test_raillabel/format/test_seg3d.py
+++ b/tests/test_raillabel/format/test_seg3d.py
@@ -19,7 +19,7 @@ def seg3d_json(
 ) -> JSONVec:
     return JSONVec(
         uid="d52e2b25-0B48-4899-86d5-4bc41be6b7d3",
-        name="rgb_middle__seg3d__person",
+        name="lidar__vec__person",
         val=[1234, 5678],
         coordinate_system="lidar",
         attributes=attributes_multiple_types_json,
@@ -57,5 +57,10 @@ def test_name(seg3d):
     assert actual == "lidar__vec__person"
 
 
+def test_to_json(seg3d, seg3d_json, seg3d_id):
+    actual = seg3d.to_json(seg3d_id, object_type="person")
+    assert actual == seg3d_json
+
+
 if __name__ == "__main__":
     pytest.main([__file__, "-v"])