self.settings._add(FloatSpinSetting("preview_extrusion_width",0.5,0,10,_("Preview extrusion width"),_("Width of Extrusion in Preview"),"UI"))
self.settings._add(FloatSpinSetting("preview_extrusion_width",0.5,0,10,_("Preview extrusion width"),_("Width of Extrusion in Preview"),"UI"),self.update_gviz_params)