diff --git a/src/PlusDataCollection/Haptics/vtkPlusPolydataForce.cxx b/src/PlusDataCollection/Haptics/vtkPlusPolydataForce.cxx
index 62c29bd09..3e4ead181 100644
--- a/src/PlusDataCollection/Haptics/vtkPlusPolydataForce.cxx
+++ b/src/PlusDataCollection/Haptics/vtkPlusPolydataForce.cxx
@@ -10,6 +10,8 @@ See License.txt for details.
 #include "vtkPolyData.h"
 #include "vtkPlusPolydataForce.h"
 #include "vtkMatrix4x4.h"
+
+using namespace std;
 
 //----------------------------------------------------------------------------