diff --git a/src/Mod/Part/App/FeaturePartBoolean.cpp b/src/Mod/Part/App/FeaturePartBoolean.cpp
index 0d63d309c1..cab2d1b32f 100644
--- a/src/Mod/Part/App/FeaturePartBoolean.cpp
+++ b/src/Mod/Part/App/FeaturePartBoolean.cpp
@@ -73,7 +73,11 @@ App::DocumentObjectExecReturn *Boolean::execute(void)
 
         // Now, let's get the TopoDS_Shape
         TopoDS_Shape BaseShape = base->Shape.getValue();
+        if (BaseShape.IsNull())
+            throw Base::Exception("Base shape is null");
         TopoDS_Shape ToolShape = tool->Shape.getValue();
+        if (ToolShape.IsNull())
+            throw Base::Exception("Tool shape is null");
 
         std::auto_ptr<BRepAlgoAPI_BooleanOperation> mkBool(makeOperation(BaseShape, ToolShape));
         if (!mkBool->IsDone()) {
@@ -81,7 +85,7 @@ App::DocumentObjectExecReturn *Boolean::execute(void)
         }
         TopoDS_Shape resShape = mkBool->Shape();
         if (resShape.IsNull()) {
-            return new App::DocumentObjectExecReturn("Resulting shape is invalid");
+            return new App::DocumentObjectExecReturn("Resulting shape is null");
         }
         Base::Reference<ParameterGrp> hGrp = App::GetApplication().GetUserParameter()
             .GetGroup("BaseApp")->GetGroup("Preferences")->GetGroup("Mod/Part/Boolean");
diff --git a/src/Mod/Part/App/FeaturePartFuse.cpp b/src/Mod/Part/App/FeaturePartFuse.cpp
index 9444524c3f..ffa7db2881 100644
--- a/src/Mod/Part/App/FeaturePartFuse.cpp
+++ b/src/Mod/Part/App/FeaturePartFuse.cpp
@@ -87,7 +87,12 @@ App::DocumentObjectExecReturn *MultiFuse::execute(void)
         try {
             std::vector<ShapeHistory> history;
             TopoDS_Shape resShape = s.front();
+            if (resShape.IsNull())
+                throw Base::Exception("Input shape is null");
             for (std::vector<TopoDS_Shape>::iterator it = s.begin()+1; it != s.end(); ++it) {
+                if (it->IsNull())
+                    throw Base::Exception("Input shape is null");
+
                 // Let's call algorithm computing a fuse operation:
                 BRepAlgoAPI_Fuse mkFuse(resShape, *it);
                 // Let's check if the fusion has been successful
@@ -108,7 +113,7 @@ App::DocumentObjectExecReturn *MultiFuse::execute(void)
                 }
             }
             if (resShape.IsNull())
-                throw Base::Exception("Resulting shape is invalid");
+                throw Base::Exception("Resulting shape is null");
 
             Base::Reference<ParameterGrp> hGrp = App::GetApplication().GetUserParameter()
                 .GetGroup("BaseApp")->GetGroup("Preferences")->GetGroup("Mod/Part/Boolean");
diff --git a/src/Mod/Part/App/TopoShape.cpp b/src/Mod/Part/App/TopoShape.cpp
index dc577d5717..81bc104d93 100644
--- a/src/Mod/Part/App/TopoShape.cpp
+++ b/src/Mod/Part/App/TopoShape.cpp
@@ -1278,30 +1278,50 @@ bool TopoShape::isClosed() const
 
 TopoDS_Shape TopoShape::cut(TopoDS_Shape shape) const
 {
+    if (this->_Shape.IsNull())
+        Standard_Failure::Raise("Base shape is null");
+    if (shape.IsNull())
+        Standard_Failure::Raise("Tool shape is null");
     BRepAlgoAPI_Cut mkCut(this->_Shape, shape);
     return mkCut.Shape();
 }
 
 TopoDS_Shape TopoShape::common(TopoDS_Shape shape) const
 {
+    if (this->_Shape.IsNull())
+        Standard_Failure::Raise("Base shape is null");
+    if (shape.IsNull())
+        Standard_Failure::Raise("Tool shape is null");
     BRepAlgoAPI_Common mkCommon(this->_Shape, shape);
     return mkCommon.Shape();
 }
 
 TopoDS_Shape TopoShape::fuse(TopoDS_Shape shape) const
 {
+    if (this->_Shape.IsNull())
+        Standard_Failure::Raise("Base shape is null");
+    if (shape.IsNull())
+        Standard_Failure::Raise("Tool shape is null");
     BRepAlgoAPI_Fuse mkFuse(this->_Shape, shape);
     return mkFuse.Shape();
 }
 
 TopoDS_Shape TopoShape::oldFuse(TopoDS_Shape shape) const
 {
+    if (this->_Shape.IsNull())
+        Standard_Failure::Raise("Base shape is null");
+    if (shape.IsNull())
+        Standard_Failure::Raise("Tool shape is null");
     BRepAlgo_Fuse mkFuse(this->_Shape, shape);
     return mkFuse.Shape();
 }
 
 TopoDS_Shape TopoShape::section(TopoDS_Shape shape) const
 {
+    if (this->_Shape.IsNull())
+        Standard_Failure::Raise("Base shape is null");
+    if (shape.IsNull())
+        Standard_Failure::Raise("Tool shape is null");
     BRepAlgoAPI_Section mkSection(this->_Shape, shape);
     return mkSection.Shape();
 }