diff --git a/ChangeLog.txt b/ChangeLog.txt
index 187a2e4e0..6bae0f05a 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -33,6 +33,7 @@
 - [#514] Read only setting not working properly.
 - [#480] New tool: Midpoint between two points.
 - [#496] Selector for selecting which pieces to print.
+- [#520] Improve Union tool. An option to select about original pieces.
 
 # Version 0.4.5
 - [#435] Valentina doesn't change the cursor.
diff --git a/src/libs/vtools/dialogs/tools/dialoguniondetails.cpp b/src/libs/vtools/dialogs/tools/dialoguniondetails.cpp
index 45174be35..cc256a33d 100644
--- a/src/libs/vtools/dialogs/tools/dialoguniondetails.cpp
+++ b/src/libs/vtools/dialogs/tools/dialoguniondetails.cpp
@@ -51,6 +51,12 @@ DialogUnionDetails::~DialogUnionDetails()
     delete ui;
 }
 
+//---------------------------------------------------------------------------------------------------------------------
+bool DialogUnionDetails::RetainPieces() const
+{
+    return ui->checkBox->isChecked();
+}
+
 //---------------------------------------------------------------------------------------------------------------------
 /**
  * @brief ChoosedObject gets id and type of selected object. Save correct data and ignore wrong.
diff --git a/src/libs/vtools/dialogs/tools/dialoguniondetails.h b/src/libs/vtools/dialogs/tools/dialoguniondetails.h
index 5f7290d6a..90fc8df01 100644
--- a/src/libs/vtools/dialogs/tools/dialoguniondetails.h
+++ b/src/libs/vtools/dialogs/tools/dialoguniondetails.h
@@ -50,6 +50,8 @@ public:
     quint32          getD2() const;
     int        getIndexD1() const;
     int        getIndexD2() const;
+
+    bool RetainPieces() const;
 public slots:
     virtual void ChosenObject(quint32 id, const SceneObject &type) Q_DECL_OVERRIDE;
 private:
diff --git a/src/libs/vtools/dialogs/tools/dialoguniondetails.ui b/src/libs/vtools/dialogs/tools/dialoguniondetails.ui
index 6d207580b..6d9c2e68c 100644
--- a/src/libs/vtools/dialogs/tools/dialoguniondetails.ui
+++ b/src/libs/vtools/dialogs/tools/dialoguniondetails.ui
@@ -10,7 +10,7 @@
     <x>0</x>
     <y>0</y>
     <width>300</width>
-    <height>78</height>
+    <height>96</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -24,13 +24,20 @@
    <bool>false</bool>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout">
-   <item alignment="Qt::AlignHCenter">
+   <item>
     <widget class="QLabel" name="label">
      <property name="text">
       <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p&gt;Do you really want to unite details?&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
      </property>
     </widget>
    </item>
+   <item>
+    <widget class="QCheckBox" name="checkBox">
+     <property name="text">
+      <string>Retain original pieces</string>
+     </property>
+    </widget>
+   </item>
    <item>
     <widget class="QDialogButtonBox" name="buttonBox">
      <property name="orientation">
diff --git a/src/libs/vtools/tools/vtooluniondetails.cpp b/src/libs/vtools/tools/vtooluniondetails.cpp
index cad29dd6f..6f82a9b3d 100644
--- a/src/libs/vtools/tools/vtooluniondetails.cpp
+++ b/src/libs/vtools/tools/vtooluniondetails.cpp
@@ -520,9 +520,10 @@ VToolUnionDetails* VToolUnionDetails::Create(DialogTool *dialog, VMainGraphicsSc
     VDetail d2 = data->GetDetail(dialogTool->getD2());
     quint32 indexD1 = static_cast<quint32>(dialogTool->getIndexD1());
     quint32 indexD2 = static_cast<quint32>(dialogTool->getIndexD2());
+    const bool retainPieces = dialogTool->RetainPieces();
     qApp->getUndoStack()->beginMacro(tr("union details"));
     VToolUnionDetails* tool = Create(0, d1, d2, dialogTool->getD1(), dialogTool->getD2(), indexD1, indexD2, scene,
-                                     doc, data, Document::FullParse, Source::FromGui);
+                                     doc, data, Document::FullParse, Source::FromGui, retainPieces);
     qApp->getUndoStack()->endMacro();
     return tool;
 }
@@ -546,7 +547,8 @@ VToolUnionDetails* VToolUnionDetails::Create(DialogTool *dialog, VMainGraphicsSc
 VToolUnionDetails* VToolUnionDetails::Create(const quint32 _id, const VDetail &d1, const VDetail &d2,
                                              const quint32 &d1id, const quint32 &d2id, const quint32 &indexD1,
                                              const quint32 &indexD2, VMainGraphicsScene *scene, VAbstractPattern *doc,
-                                             VContainer *data, const Document &parse, const Source &typeCreation)
+                                             VContainer *data, const Document &parse, const Source &typeCreation,
+                                             bool retainPieces)
 {
     VToolUnionDetails *unionDetails = 0;
     quint32 id = _id;
@@ -639,17 +641,22 @@ VToolUnionDetails* VToolUnionDetails::Create(const quint32 _id, const VDetail &d
         QHash<quint32, VDataTool*>* tools = doc->getTools();
         SCASSERT(tools != nullptr);
 
+        if (not retainPieces)
         {
-            VToolDetail *toolDet = qobject_cast<VToolDetail*>(tools->value(d1id));
-            SCASSERT(toolDet != nullptr);
-            bool ask = false;
-            toolDet->Remove(ask);
-        }
+            {
+                VToolDetail *toolDet = qobject_cast<VToolDetail*>(tools->value(d1id));
+                SCASSERT(toolDet != nullptr);
+                bool ask = false;
+                toolDet->Remove(ask);
+            }
 
-        VToolDetail *toolDet = qobject_cast<VToolDetail*>(tools->value(d2id));
-        SCASSERT(toolDet != nullptr);
-        bool ask = false;
-        toolDet->Remove(ask);
+            {
+                VToolDetail *toolDet = qobject_cast<VToolDetail*>(tools->value(d2id));
+                SCASSERT(toolDet != nullptr);
+                const bool ask = false;
+                toolDet->Remove(ask);
+            }
+        }
 
         SCASSERT(not children.isEmpty())
         SaveChildren(doc, id, children);
diff --git a/src/libs/vtools/tools/vtooluniondetails.h b/src/libs/vtools/tools/vtooluniondetails.h
index 1e3ab77a5..c4439d139 100644
--- a/src/libs/vtools/tools/vtooluniondetails.h
+++ b/src/libs/vtools/tools/vtooluniondetails.h
@@ -52,7 +52,8 @@ public:
                                      const quint32 &d2id, const quint32 &indexD1, const quint32 &indexD2,
                                      VMainGraphicsScene *scene, VAbstractPattern *doc, VContainer *data,
                                      const Document &parse,
-                                     const Source &typeCreation);
+                                     const Source &typeCreation,
+                                     bool retainPieces = false);
     static void  PointsOnEdge(const VDetail &d, const quint32 &index, VPointF &p1, VPointF &p2, VContainer *data);
     static void  FindIndexJ(const qint32 &pointsD2, const VDetail &d2, const quint32 &indexD2, qint32 &j);
     static QVector<VDetail> GetDetailFromFile(VAbstractPattern *doc, const QDomElement &domElement);