diff --git a/src/brep/brep.cpp b/src/brep/brep.cpp
index dbf8448..60593a6 100644
--- a/src/brep/brep.cpp
+++ b/src/brep/brep.cpp
@@ -17,9 +17,9 @@ int BrepModel::add_edge(int v0, int v1) {
 }
 
 int BrepModel::add_edge(int v0, int v1, const curves::NurbsCurve& curve) {
-    int id = next_id_++;
-    edges_.push_back({id, v0, v1, std::make_shared<curves::NurbsCurve>(curve), false});
-    return id;
+    int idx = static_cast<int>(edges_.size());
+    edges_.push_back({next_id_++, v0, v1, std::make_shared<curves::NurbsCurve>(curve), false});
+    return idx;
 }
 
 int BrepModel::add_loop(const std::vector<int>& edge_ids, bool outer) {