diff --git a/Gui/VtkVis/VtkCompositeFilter.cpp b/Gui/VtkVis/VtkCompositeFilter.cpp
index 13e186bc346d422faa86f88f21127cadfa48b9d6..3439caf4ecd42097a155b11fed0d6735416c5999 100644
--- a/Gui/VtkVis/VtkCompositeFilter.cpp
+++ b/Gui/VtkVis/VtkCompositeFilter.cpp
@@ -24,7 +24,7 @@
 
 VtkCompositeFilter::VtkCompositeFilter(vtkAlgorithm* inputAlgorithm)
 	: _inputDataObjectType(0), _outputDataObjectType(1),
-	  _inputAlgorithm(inputAlgorithm)
+	  _inputAlgorithm(inputAlgorithm), _outputAlgorithm(nullptr)
 {
 }