diff --git a/Framework/Geometry/inc/MantidGeometry/Rendering/GeometryTriangulator.h b/Framework/Geometry/inc/MantidGeometry/Rendering/GeometryTriangulator.h
index a457c8f71f4c3e2b3651bd1010d5c3a52d3584f4..0e7cb58854572ae2d97c7c6b1914c1435e4745e6 100644
--- a/Framework/Geometry/inc/MantidGeometry/Rendering/GeometryTriangulator.h
+++ b/Framework/Geometry/inc/MantidGeometry/Rendering/GeometryTriangulator.h
@@ -44,8 +44,8 @@ private:
   size_t m_nPoints;
   std::vector<double> m_points;  ///< double array or points
   std::vector<uint32_t> m_faces; ///< Integer array of faces
-  const CSGObject *m_csgObj;     ///< Input Object
-  const MeshObject *m_meshObj;
+  const CSGObject *m_csgObj = nullptr; ///< Input Object
+  const MeshObject *m_meshObj = nullptr;
   void checkTriangulated();
 
 public: