+/// Origin point of the sketcher in 3D space
+const std::string SKETCH_ATTR_ORIGIN("Origin");
+/// Vector X inside of the sketch plane
+const std::string SKETCH_ATTR_DIRX("DirX");
+/// Vector Y inside of the sketch plane
+const std::string SKETCH_ATTR_DIRY("DirY");
+/// Vector Z, normal to the sketch plane
+const std::string SKETCH_ATTR_NORM("Norm");
+/// All features of this sketch (list of references)
+const std::string SKETCH_ATTR_FEATURES("Features");