diff --git a/src/common/ml_document/mesh_model.cpp b/src/common/ml_document/mesh_model.cpp
index 2524576a1..6cd30208f 100644
--- a/src/common/ml_document/mesh_model.cpp
+++ b/src/common/ml_document/mesh_model.cpp
@@ -35,7 +35,7 @@
 
 using namespace vcg;
 
-MeshModel::MeshModel(unsigned int id, const QString& fullFileName, const QString& labelName) :
+MeshModel::MeshModel(int id, const QString& fullFileName, const QString& labelName) :
 	visible(true)
 {
 	/*glw.m = &(cm);*/
diff --git a/src/common/ml_document/mesh_model.h b/src/common/ml_document/mesh_model.h
index 920ae10b3..d5abb402c 100644
--- a/src/common/ml_document/mesh_model.h
+++ b/src/common/ml_document/mesh_model.h
@@ -121,14 +121,14 @@ public:
 		MM_ALL            = 0xffffffff
 	};
 
-	MeshModel(unsigned int id, const QString& fullFileName, const QString& labelName);
+	MeshModel(int id, const QString& fullFileName, const QString& labelName);
 	~MeshModel()
 	{
 	}
 
 	void clear();
 	void updateBoxAndNormals(); // This is the STANDARD method that you should call after changing coords.
-	inline unsigned int id() const {return _id;}
+	inline int id() const {return _id;}
 
 	int idInFile() const {return idInsideFile;}
 	void setIdInFile(int id) {idInsideFile = id;}
@@ -199,7 +199,7 @@ private:
 	bool visible; // used in rendering; Needed for toggling on and off the meshes
 	QString fullPathFileName;
 	QString _label;
-	unsigned int _id;
+	int _id;
 	bool modified;
 
 	//this is an id used for meshes that are loaded from files