diff --git a/src/skeletondocument.cpp b/src/skeletondocument.cpp
index fbf60e19..fc1a5372 100644
--- a/src/skeletondocument.cpp
+++ b/src/skeletondocument.cpp
@@ -5,6 +5,8 @@
 #include "skeletondocument.h"
 #include "util.h"
 
+unsigned long SkeletonDocument::m_maxSnapshot = 1000;
+
 SkeletonDocument::SkeletonDocument() :
     m_resultMeshIsObsolete(false),
     m_resultMesh(nullptr),
@@ -33,7 +35,7 @@ void SkeletonDocument::removeEdge(QUuid edgeId)
         qDebug() << "Find edge failed:" << edgeId;
         return;
     }
-    if (isPartLocked(edge->partId))
+    if (isPartReadonly(edge->partId))
         return;
     const SkeletonPart *oldPart = findPart(edge->partId);
     if (nullptr == oldPart) {
@@ -94,7 +96,7 @@ void SkeletonDocument::removeNode(QUuid nodeId)
         qDebug() << "Find node failed:" << nodeId;
         return;
     }
-    if (isPartLocked(node->partId))
+    if (isPartReadonly(node->partId))
         return;
     const SkeletonPart *oldPart = findPart(node->partId);
     if (nullptr == oldPart) {
@@ -174,7 +176,7 @@ void SkeletonDocument::addNode(float x, float y, float z, float radius, QUuid fr
             return;
         }
         partId = fromNode->partId;
-        if (isPartLocked(partId))
+        if (isPartReadonly(partId))
             return;
     }
     SkeletonNode node;
@@ -243,7 +245,7 @@ void SkeletonDocument::addEdge(QUuid fromNodeId, QUuid toNodeId)
         return;
     }
     
-    if (isPartLocked(fromNode->partId))
+    if (isPartReadonly(fromNode->partId))
         return;
     
     toNode = findNode(toNodeId);
@@ -252,7 +254,7 @@ void SkeletonDocument::addEdge(QUuid fromNodeId, QUuid toNodeId)
         return;
     }
     
-    if (isPartLocked(toNode->partId))
+    if (isPartReadonly(toNode->partId))
         return;
     
     QUuid toPartId = toNode->partId;
@@ -339,21 +341,21 @@ void SkeletonDocument::scaleNodeByAddRadius(QUuid nodeId, float amount)
         qDebug() << "Find node failed:" << nodeId;
         return;
     }
-    if (isPartLocked(it->second.partId))
+    if (isPartReadonly(it->second.partId))
         return;
     it->second.radius += amount;
     emit nodeRadiusChanged(nodeId);
     emit skeletonChanged();
 }
 
-bool SkeletonDocument::isPartLocked(QUuid partId)
+bool SkeletonDocument::isPartReadonly(QUuid partId)
 {
     const SkeletonPart *part = findPart(partId);
     if (nullptr == part) {
         qDebug() << "Find part failed:" << partId;
         return true;
     }
-    return part->locked;
+    return part->locked || !part->visible;
 }
 
 void SkeletonDocument::moveNodeBy(QUuid nodeId, float x, float y, float z)
@@ -363,7 +365,7 @@ void SkeletonDocument::moveNodeBy(QUuid nodeId, float x, float y, float z)
         qDebug() << "Find node failed:" << nodeId;
         return;
     }
-    if (isPartLocked(it->second.partId))
+    if (isPartReadonly(it->second.partId))
         return;
     it->second.x += x;
     it->second.y += y;
@@ -379,7 +381,7 @@ void SkeletonDocument::setNodeOrigin(QUuid nodeId, float x, float y, float z)
         qDebug() << "Find node failed:" << nodeId;
         return;
     }
-    if (isPartLocked(it->second.partId))
+    if (isPartReadonly(it->second.partId))
         return;
     it->second.x = x;
     it->second.y = y;
@@ -395,7 +397,7 @@ void SkeletonDocument::setNodeRadius(QUuid nodeId, float radius)
         qDebug() << "Find node failed:" << nodeId;
         return;
     }
-    if (isPartLocked(it->second.partId))
+    if (isPartReadonly(it->second.partId))
         return;
     it->second.radius = radius;
     emit nodeRadiusChanged(nodeId);
@@ -555,6 +557,8 @@ void SkeletonDocument::fromSnapshot(const SkeletonSnapshot &snapshot)
     nodeMap.clear();
     edgeMap.clear();
     partMap.clear();
+    partIds.clear();
+    emit partListChanged();
     
     for (const auto &nodeKv : snapshot.nodes) {
         SkeletonNode node(QUuid(nodeKv.first));
@@ -603,6 +607,7 @@ void SkeletonDocument::fromSnapshot(const SkeletonSnapshot &snapshot)
     }
     
     emit partListChanged();
+    emit skeletonChanged();
 }
 
 const char *SkeletonNodeRootMarkModeToString(SkeletonNodeRootMarkMode mode)
@@ -772,3 +777,33 @@ void SkeletonDocument::setPartSubdivState(QUuid partId, bool subdived)
     emit skeletonChanged();
 }
 
+void SkeletonDocument::saveSnapshot()
+{
+    if (m_undoItems.size() + 1 > m_maxSnapshot)
+        m_undoItems.pop_front();
+    SkeletonHistoryItem item;
+    toSnapshot(&item.snapshot);
+    m_undoItems.push_back(item);
+    qDebug() << "Undo items:" << m_undoItems.size();
+}
+
+void SkeletonDocument::undo()
+{
+    if (m_undoItems.empty())
+        return;
+    m_redoItems.push_back(m_undoItems.back());
+    fromSnapshot(m_undoItems.back().snapshot);
+    m_undoItems.pop_back();
+    qDebug() << "Undo/Redo items:" << m_undoItems.size() << m_redoItems.size();
+}
+
+void SkeletonDocument::redo()
+{
+    if (m_redoItems.empty())
+        return;
+    m_undoItems.push_back(m_redoItems.back());
+    fromSnapshot(m_redoItems.back().snapshot);
+    m_redoItems.pop_back();
+    qDebug() << "Undo/Redo items:" << m_undoItems.size() << m_redoItems.size();
+}
+
diff --git a/src/skeletondocument.h b/src/skeletondocument.h
index 75e0209b..f87e6f8c 100644
--- a/src/skeletondocument.h
+++ b/src/skeletondocument.h
@@ -5,6 +5,7 @@
 #include <vector>
 #include <map>
 #include <set>
+#include <deque>
 #include <QImage>
 #include "skeletonsnapshot.h"
 #include "mesh.h"
@@ -148,7 +149,6 @@ public:
     std::map<QUuid, SkeletonPart> partMap;
     std::map<QUuid, SkeletonNode> nodeMap;
     std::map<QUuid, SkeletonEdge> edgeMap;
-    std::vector<SkeletonHistoryItem> historyItems;
     std::vector<QUuid> partIds;
     QImage turnaround;
     SkeletonDocumentEditMode editMode;
@@ -180,15 +180,21 @@ public slots:
     void setPartLockState(QUuid partId, bool locked);
     void setPartVisibleState(QUuid partId, bool visible);
     void setPartSubdivState(QUuid partId, bool subdived);
+    void saveSnapshot();
+    void undo();
+    void redo();
 private:
     void splitPartByNode(std::vector<std::vector<QUuid>> *groups, QUuid nodeId);
     void joinNodeAndNeiborsToGroup(std::vector<QUuid> *group, QUuid nodeId, std::set<QUuid> *visitMap, QUuid noUseEdgeId=QUuid());
     void splitPartByEdge(std::vector<std::vector<QUuid>> *groups, QUuid edgeId);
-    bool isPartLocked(QUuid partId);
+    bool isPartReadonly(QUuid partId);
 private:
     bool m_resultMeshIsObsolete;
     MeshGenerator *m_meshGenerator;
     Mesh *m_resultMesh;
+    static unsigned long m_maxSnapshot;
+    std::deque<SkeletonHistoryItem> m_undoItems;
+    std::deque<SkeletonHistoryItem> m_redoItems;
 };
 
 #endif
diff --git a/src/skeletondocumentwindow.cpp b/src/skeletondocumentwindow.cpp
index 6210acfa..93161842 100644
--- a/src/skeletondocumentwindow.cpp
+++ b/src/skeletondocumentwindow.cpp
@@ -157,6 +157,10 @@ SkeletonDocumentWindow::SkeletonDocumentWindow() :
     
     connect(changeTurnaroundButton, &QPushButton::clicked, this, &SkeletonDocumentWindow::changeTurnaround);
     
+    connect(undoButton, &QPushButton::clicked, [=]() {
+        m_document->undo();
+    });
+    
     connect(addButton, &QPushButton::clicked, [=]() {
         m_document->setEditMode(SkeletonDocumentEditMode::Add);
     });
@@ -186,6 +190,9 @@ SkeletonDocumentWindow::SkeletonDocumentWindow() :
     connect(graphicsWidget, &SkeletonGraphicsWidget::setEditMode, m_document, &SkeletonDocument::setEditMode);
     connect(graphicsWidget, &SkeletonGraphicsWidget::removeEdge, m_document, &SkeletonDocument::removeEdge);
     connect(graphicsWidget, &SkeletonGraphicsWidget::addEdge, m_document, &SkeletonDocument::addEdge);
+    connect(graphicsWidget, &SkeletonGraphicsWidget::groupOperationAdded, m_document, &SkeletonDocument::saveSnapshot);
+    connect(graphicsWidget, &SkeletonGraphicsWidget::undo, m_document, &SkeletonDocument::undo);
+    connect(graphicsWidget, &SkeletonGraphicsWidget::redo, m_document, &SkeletonDocument::redo);
     
     connect(m_document, &SkeletonDocument::nodeAdded, graphicsWidget, &SkeletonGraphicsWidget::nodeAdded);
     connect(m_document, &SkeletonDocument::nodeRemoved, graphicsWidget, &SkeletonGraphicsWidget::nodeRemoved);
diff --git a/src/skeletongraphicswidget.cpp b/src/skeletongraphicswidget.cpp
index d7f4024c..fa21596a 100644
--- a/src/skeletongraphicswidget.cpp
+++ b/src/skeletongraphicswidget.cpp
@@ -359,10 +359,12 @@ bool SkeletonGraphicsWidget::wheel(QWheelEvent *event)
                     emit scaleNodeByAddRadius(nodeItem->id(), unifiedDelta);
                 }
             }
+            emit groupOperationAdded();
             return true;
         } else if (m_hoveredNodeItem) {
             float unifiedDelta = sceneRadiusToUnified(delta);
             emit scaleNodeByAddRadius(m_hoveredNodeItem->id(), unifiedDelta);
+            emit groupOperationAdded();
             return true;
         }
     }
@@ -379,6 +381,7 @@ bool SkeletonGraphicsWidget::mouseRelease(QMouseEvent *event)
         }
         if (m_moveStarted) {
             m_moveStarted = false;
+            emit groupOperationAdded();
         }
         if (m_rangeSelectionStarted) {
             m_selectionItem->hide();
@@ -428,6 +431,7 @@ bool SkeletonGraphicsWidget::mousePress(QMouseEvent *event)
                         if (m_document->findEdgeByNodes(m_addFromNodeItem->id(), m_hoveredNodeItem->id()))
                             return true;
                         emit addEdge(m_addFromNodeItem->id(), m_hoveredNodeItem->id());
+                        emit groupOperationAdded();
                         return true;
                     }
                 }
@@ -452,6 +456,7 @@ bool SkeletonGraphicsWidget::mousePress(QMouseEvent *event)
                 m_lastAddedZ = unifiedSidePos.x();
                 qDebug() << "Emit add node " << m_lastAddedX << m_lastAddedY << m_lastAddedZ;
                 emit addNode(unifiedMainPos.x(), unifiedMainPos.y(), unifiedSidePos.x(), sceneRadiusToUnified(m_cursorNodeItem->radius()), nullptr == m_addFromNodeItem ? QUuid() : m_addFromNodeItem->id());
+                emit groupOperationAdded();
                 return true;
             }
         } else if (SkeletonDocumentEditMode::Select == m_document->editMode) {
@@ -533,6 +538,7 @@ bool SkeletonGraphicsWidget::keyPress(QKeyEvent *event)
             }
         }
         if (processed) {
+            emit groupOperationAdded();
             return true;
         }
     } else if (event->key() == Qt::Key_A) {
@@ -542,6 +548,20 @@ bool SkeletonGraphicsWidget::keyPress(QKeyEvent *event)
             emit setEditMode(SkeletonDocumentEditMode::Add);
         }
         return true;
+    } else if (event->key() == Qt::Key_Z) {
+        if (QGuiApplication::queryKeyboardModifiers().testFlag(Qt::ControlModifier)) {
+            if (QGuiApplication::queryKeyboardModifiers().testFlag(Qt::ShiftModifier)) {
+                emit redo();
+            } else {
+                emit undo();
+            }
+        }
+    } else if (event->key() == Qt::Key_Y) {
+        if (QGuiApplication::queryKeyboardModifiers().testFlag(Qt::ControlModifier)) {
+            if (!QGuiApplication::queryKeyboardModifiers().testFlag(Qt::ShiftModifier)) {
+                emit redo();
+            }
+        }
     }
     return false;
 }
diff --git a/src/skeletongraphicswidget.h b/src/skeletongraphicswidget.h
index 1d02c5c9..21a07eba 100644
--- a/src/skeletongraphicswidget.h
+++ b/src/skeletongraphicswidget.h
@@ -259,6 +259,9 @@ signals:
     void removeEdge(QUuid edgeId);
     void addEdge(QUuid fromNodeId, QUuid toNodeId);
     void cursorChanged();
+    void groupOperationAdded();
+    void undo();
+    void redo();
 public:
     SkeletonGraphicsWidget(const SkeletonDocument *document);
     std::map<QUuid, std::pair<SkeletonGraphicsNodeItem *, SkeletonGraphicsNodeItem *>> nodeItemMap;