diff --git a/Gui/VtkVis/VtkCompositePointToGlyphFilter.cpp b/Gui/VtkVis/VtkCompositePointToGlyphFilter.cpp
index 77a777bd7e41520d9a3d71dd08690012152373c9..8d7ecd83029dd38e20901860c136dd63698b5bc9 100644
--- a/Gui/VtkVis/VtkCompositePointToGlyphFilter.cpp
+++ b/Gui/VtkVis/VtkCompositePointToGlyphFilter.cpp
@@ -21,7 +21,7 @@
 #include <vtkSphereSource.h>
 
 VtkCompositePointToGlyphFilter::VtkCompositePointToGlyphFilter( vtkAlgorithm* inputAlgorithm )
-	: VtkCompositeFilter(inputAlgorithm)
+	: VtkCompositeFilter(inputAlgorithm), _glyphSource(nullptr)
 {
 	this->init();
 }