diff --git a/GUI/ba3d/def.h b/GUI/ba3d/def.h
index ae3f5e57d874a4c6375c3ba2f7b38590c956f21c..e20ff8fb3c598c4c45394e6c5c833b02155e32a5 100644
--- a/GUI/ba3d/def.h
+++ b/GUI/ba3d/def.h
@@ -34,6 +34,7 @@ struct Vector3D {
     Vector3D(float, float, float);
 
     Vector3D(const Vector3D&) = default;
+    Vector3D& operator=(const Vector3D&) = default;
 
     Vector3D(QVector3D const&);
     operator QVector3D() const;