diff --git a/vcg/complex/allocate.h b/vcg/complex/allocate.h
index c1691fd9..308305f9 100644
--- a/vcg/complex/allocate.h
+++ b/vcg/complex/allocate.h
@@ -34,27 +34,27 @@ namespace tri {
 */
 
 template<class MeshType>
-size_t Index(MeshType &m, const typename MeshType::VertexType &v) {return &v-&*m.vert.begin();}
+size_t Index(const MeshType &m, const typename MeshType::VertexType &v) {return &v-&*m.vert.begin();}
 template<class MeshType>
-size_t Index(MeshType &m, const typename MeshType::FaceType &f) {return &f-&*m.face.begin();}
+size_t Index(const MeshType &m, const typename MeshType::FaceType &f) {return &f-&*m.face.begin();}
 template<class MeshType>
-size_t Index(MeshType &m, const typename MeshType::EdgeType &e) {return &e-&*m.edge.begin();}
+size_t Index(const MeshType &m, const typename MeshType::EdgeType &e) {return &e-&*m.edge.begin();}
 template<class MeshType>
-size_t Index(MeshType &m, const typename MeshType::HEdgeType &h) {return &h-&*m.hedge.begin();}
+size_t Index(const MeshType &m, const typename MeshType::HEdgeType &h) {return &h-&*m.hedge.begin();}
 template <class MeshType>
-size_t Index(MeshType &m, const typename MeshType::TetraType &t) { return &t - &*m.tetra.begin(); }
+size_t Index(const MeshType &m, const typename MeshType::TetraType &t) { return &t - &*m.tetra.begin(); }
 
 
 template<class MeshType>
-size_t Index(MeshType &m, const typename MeshType::VertexType *vp) {return vp-&*m.vert.begin();}
+size_t Index(const MeshType &m, const typename MeshType::VertexType *vp) {return vp-&*m.vert.begin();}
 template<class MeshType>
-size_t Index(MeshType &m, const typename MeshType::FaceType * fp) {return fp-&*m.face.begin();}
+size_t Index(const MeshType &m, const typename MeshType::FaceType * fp) {return fp-&*m.face.begin();}
 template<class MeshType>
-size_t Index(MeshType &m, const typename MeshType::EdgeType*  e) {return e-&*m.edge.begin();}
+size_t Index(const MeshType &m, const typename MeshType::EdgeType*  e) {return e-&*m.edge.begin();}
 template<class MeshType>
-size_t Index(MeshType &m, const typename MeshType::HEdgeType*  h) {return h-&*m.hedge.begin();}
+size_t Index(const MeshType &m, const typename MeshType::HEdgeType*  h) {return h-&*m.hedge.begin();}
 template <class MeshType>
-size_t Index(MeshType &m, const typename MeshType::TetraType *t) { return t - &*m.tetra.begin(); }
+size_t Index(const MeshType &m, const typename MeshType::TetraType *t) { return t - &*m.tetra.begin(); }
 
 
 template<class MeshType>