diff --git a/pychunkedgraph/meshing/meshgen.py b/pychunkedgraph/meshing/meshgen.py
index be708ae55..eea04c9cd 100644
--- a/pychunkedgraph/meshing/meshgen.py
+++ b/pychunkedgraph/meshing/meshgen.py
@@ -71,6 +71,8 @@ def simplify(cg, fragment, fragment_id, lod=None):
     )
     vertices, faces, _ = simplifier.getMesh()
     vertices = vertices * scale
+
+    fragment["num_vertices"] = len(vertices)
     fragment["vertices"] = vertices.flatten()
     fragment["faces"] = faces.flatten()
     return fragment