diff --git a/ACKNOWLEDGEMENTS.html b/ACKNOWLEDGEMENTS.html
index 563696b3..354bd46d 100644
--- a/ACKNOWLEDGEMENTS.html
+++ b/ACKNOWLEDGEMENTS.html
@@ -1218,4 +1218,10 @@ https://www.reddit.com/r/gamedev/comments/5iuf3h/i_am_writting_a_3d_monster_mode
 <h1>Coons patch</h1>
 <pre>
     https://en.wikipedia.org/wiki/Coons_patch
+</pre>
+
+<h1>T. Y. ZHANG and C. Y. SUEN</h1>
+<pre>
+    A Fast Parallel Algorithm for Thinning Digital Patterns
+    https://dl.acm.org/citation.cfm?id=358023
 </pre>
\ No newline at end of file
diff --git a/docs/shortcuts.rst b/docs/shortcuts.rst
index 85169037..72aa35ed 100644
--- a/docs/shortcuts.rst
+++ b/docs/shortcuts.rst
@@ -34,6 +34,8 @@ Keyboard
 +----------------------+--------------------------------------------------------------------------+
 | D                    | Enter Paint Mode                                                         |
 +----------------------+--------------------------------------------------------------------------+
+| G                    | Enter Mark Mode                                                          |
++----------------------+--------------------------------------------------------------------------+
 | CTRL + S             | Save                                                                     |
 +----------------------+--------------------------------------------------------------------------+
 | CTRL + Z             | Undo                                                                     |
diff --git a/dust3d.pro b/dust3d.pro
index b220abc7..6103a604 100644
--- a/dust3d.pro
+++ b/dust3d.pro
@@ -480,6 +480,9 @@ HEADERS += src/booleanmesh.h
 SOURCES += src/imageskeletonextractor.cpp
 HEADERS += src/imageskeletonextractor.h
 
+SOURCES += src/contourtopartconverter.cpp
+HEADERS += src/contourtopartconverter.h
+
 SOURCES += src/main.cpp
 
 HEADERS += src/version.h
diff --git a/languages/dust3d_zh_CN.ts b/languages/dust3d_zh_CN.ts
index 050df67c..989504f7 100644
--- a/languages/dust3d_zh_CN.ts
+++ b/languages/dust3d_zh_CN.ts
@@ -386,6 +386,10 @@ Tips:
         <source>Create Wrap Parts</source>
         <translation>创建包裹部件</translation>
     </message>
+    <message>
+        <source>Marker pen</source>
+        <translation>马克笔</translation>
+    </message>
 </context>
 <context>
     <name>ExportPreviewWidget</name>
diff --git a/src/contourtopartconverter.cpp b/src/contourtopartconverter.cpp
new file mode 100644
index 00000000..2bfbb185
--- /dev/null
+++ b/src/contourtopartconverter.cpp
@@ -0,0 +1,260 @@
+#include <QImage>
+#include <QPainter>
+#include <cmath>
+#include <QUuid>
+#include <cmath>
+#include <QTransform>
+#include "contourtopartconverter.h"
+#include "imageskeletonextractor.h"
+#include "util.h"
+
+const float ContourToPartConverter::m_targetImageHeight = 64.0f;
+const float ContourToPartConverter::m_minEdgeLength = 0.025;
+const float ContourToPartConverter::m_radiusEpsilon = 0.0025;
+
+ContourToPartConverter::ContourToPartConverter(const QPolygonF &mainProfile,
+        const QPolygonF &sideProfile, const QSizeF &canvasSize) :
+    m_mainProfile(mainProfile),
+    m_sideProfile(sideProfile),
+    m_canvasSize(canvasSize)
+{
+}
+
+void ContourToPartConverter::process()
+{
+    convert();
+    emit finished();
+}
+
+const Snapshot &ContourToPartConverter::getSnapshot()
+{
+    return m_snapshot;
+}
+
+void ContourToPartConverter::extractSkeleton(const QPolygonF &polygon,
+        std::vector<std::pair<QVector2D, float>> *skeleton)
+{
+    auto originalBoundingBox = polygon.boundingRect();
+    QPointF polygonTopLeft = originalBoundingBox.topLeft();
+    
+    float scaleFactor = m_targetImageHeight / originalBoundingBox.height();
+    
+    QTransform transform;
+    transform = transform.scale(scaleFactor, scaleFactor);
+    QPolygonF scaledPolygon = transform.map(polygon);
+    
+    QRectF boundingBox = scaledPolygon.boundingRect();
+    QImage *image = new QImage(boundingBox.width() + 4, boundingBox.height() + 4, QImage::Format_Grayscale8);
+    image->fill(QColor(255, 255, 255));
+    
+    qreal offsetX = 1 - boundingBox.left();
+    qreal offsetY = 1 - boundingBox.top();
+    
+    QPainterPath path;
+    path.addPolygon(scaledPolygon.translated(offsetX, offsetY));
+    
+    QPainter painter;
+    painter.begin(image);
+    painter.setPen(Qt::PenStyle::NoPen);
+    painter.fillPath(path, Qt::black);
+    painter.end();
+    
+    ImageSkeletonExtractor imageSkeletonExtractor;
+    imageSkeletonExtractor.setImage(image);
+    imageSkeletonExtractor.extract();
+    
+    std::vector<std::pair<int, int>> imageSkeleton;
+    int imageArea = imageSkeletonExtractor.getArea();
+    imageSkeletonExtractor.getSkeleton(&imageSkeleton);
+    const std::set<std::pair<int, int>> &blackPixels = imageSkeletonExtractor.getBlackPixels();
+    
+    std::vector<std::pair<int, int>> selectedNodes;
+    if (imageSkeleton.size() >= 2) {
+        int targetLength = std::ceil(0.5 * (float)imageArea / imageSkeleton.size());
+        int minLength = m_minEdgeLength * imageSkeleton.size();
+        if (targetLength < minLength)
+            targetLength = minLength;
+        size_t newInsertNum = imageSkeleton.size() / targetLength;
+        if (newInsertNum < 1)
+            newInsertNum = 1;
+        if (newInsertNum > 100)
+            newInsertNum = 100;
+        float stepFactor = 1.0 / (newInsertNum + 1);
+        float factor = stepFactor;
+        selectedNodes.push_back(imageSkeleton[0]);
+        for (size_t i = 0; i < newInsertNum && factor < 1.0; factor += stepFactor, ++i) {
+            size_t index = factor * imageSkeleton.size();
+            if (index <= 0 || index >= imageSkeleton.size())
+                continue;
+            selectedNodes.push_back(imageSkeleton[index]);
+        }
+        selectedNodes.push_back(imageSkeleton[imageSkeleton.size() - 1]);
+    }
+    
+    std::vector<QVector3D> selectedPositions;
+    selectedPositions.reserve(selectedNodes.size());
+    for (const auto &it: selectedNodes)
+        selectedPositions.push_back(QVector3D(it.first, it.second, 0.0f));
+    
+    std::vector<QVector3D> selectedDirections;
+    selectedDirections.reserve(selectedNodes.size());
+    for (size_t i = 0; i < selectedPositions.size(); ++i) {
+        QVector3D sumOfDirections;
+        if (i > 0) {
+            sumOfDirections += selectedPositions[i] - selectedPositions[i - 1];
+        }
+        if (i + 1 < selectedPositions.size()) {
+            sumOfDirections += selectedPositions[i + 1] - selectedPositions[i];
+        }
+        selectedDirections.push_back(sumOfDirections.normalized());
+    }
+    
+    std::vector<int> selectedRadius;
+    selectedRadius.reserve(selectedNodes.size());
+    for (size_t i = 0; i < selectedDirections.size(); ++i) {
+        selectedRadius.push_back(calculateNodeRadius(selectedPositions[i], selectedDirections[i],
+            blackPixels));
+    }
+    
+    skeleton->resize(selectedRadius.size());
+    auto canvasHeight = m_canvasSize.height();
+    for (size_t i = 0; i < skeleton->size(); ++i) {
+        const auto &node = selectedNodes[i];
+        (*skeleton)[i] = std::make_pair(QVector2D(node.first / scaleFactor + polygonTopLeft.x(),
+                node.second / scaleFactor + polygonTopLeft.y()) / canvasHeight,
+            selectedRadius[i] / scaleFactor / canvasHeight);
+    }
+}
+
+int ContourToPartConverter::calculateNodeRadius(const QVector3D &node,
+        const QVector3D &direction,
+        const std::set<std::pair<int, int>> &black)
+{
+    const QVector3D pointer = {0.0f, 0.0f, 1.0f};
+    QVector3D offsetDirection = QVector3D::crossProduct(direction, pointer);
+    int radius = 1;
+    while (true) {
+        QVector3D offset = radius * offsetDirection;
+        QVector3D sidePosition = node + offset;
+        QVector3D otherSidePosition = node - offset;
+        if (black.find(std::make_pair((int)sidePosition.x(), (int)sidePosition.y())) == black.end())
+            break;
+        if (black.find(std::make_pair((int)otherSidePosition.x(), (int)otherSidePosition.y())) == black.end())
+            break;
+        ++radius;
+    }
+    return radius;
+}
+
+void ContourToPartConverter::smoothRadius(std::vector<std::pair<QVector2D, float>> *skeleton)
+{
+    if (skeleton->empty())
+        return;
+    
+    std::vector<float> newRadius;
+    newRadius.reserve(skeleton->size() + 2);
+    newRadius.push_back(skeleton->front().second);
+    for (const auto &it: (*skeleton)) {
+        newRadius.push_back(it.second);
+    }
+    newRadius.push_back(skeleton->back().second);
+    for (size_t h = 0; h < skeleton->size(); ++h) {
+        size_t i = h + 1;
+        size_t j = h + 2;
+        (*skeleton)[h].second = (newRadius[h] +
+            newRadius[i] + newRadius[j]) / 3;
+    }
+}
+
+void ContourToPartConverter::optimizeNodes()
+{
+    auto oldNodes = m_nodes;
+    m_nodes.clear();
+    m_nodes.reserve(oldNodes.size());
+    for (size_t i = 0; i < oldNodes.size(); ++i) {
+        if (i > 0 && i + 1 < oldNodes.size()) {
+            size_t h = i - 1;
+            size_t j = i + 1;
+            if (std::abs(oldNodes[i].second - oldNodes[h].second) < m_radiusEpsilon &&
+                    std::abs(oldNodes[i].second - oldNodes[j].second) < m_radiusEpsilon) {
+                auto degrees = degreesBetweenVectors((oldNodes[i].first - oldNodes[h].first).normalized(),
+                    (oldNodes[j].first - oldNodes[i].first).normalized());
+                if (degrees < 15)
+                    continue;
+            }
+        }
+        m_nodes.push_back(oldNodes[i]);
+    }
+}
+
+void ContourToPartConverter::convert()
+{
+    std::vector<std::pair<QVector2D, float>> sideSkeleton;
+    auto mainBoundingBox = m_mainProfile.boundingRect();
+    extractSkeleton(m_sideProfile, &sideSkeleton);
+    if (!sideSkeleton.empty()) {
+        float x = mainBoundingBox.center().x() / m_canvasSize.height();
+        m_nodes.reserve(sideSkeleton.size());
+        for (size_t i = 0; i < sideSkeleton.size(); ++i) {
+            const auto &it = sideSkeleton[i];
+            m_nodes.push_back(std::make_pair(QVector3D(x, it.first.y(), it.first.x()),
+                it.second));
+        }
+    }
+    optimizeNodes();
+    nodesToSnapshot();
+}
+
+void ContourToPartConverter::nodesToSnapshot()
+{
+    if (m_nodes.empty())
+        return;
+    
+    auto partId = QUuid::createUuid();
+    auto partIdString = partId.toString();
+    std::map<QString, QString> snapshotPart;
+    snapshotPart["id"] = partIdString;
+    snapshotPart["subdived"] = "true";
+    snapshotPart["rounded"] = "true";
+    m_snapshot.parts[partIdString] = snapshotPart;
+    
+    auto componentId = QUuid::createUuid();
+    auto componentIdString = componentId.toString();
+    std::map<QString, QString> snapshotComponent;
+    snapshotComponent["id"] = componentIdString;
+    snapshotComponent["combineMode"] = "Normal";
+    snapshotComponent["linkDataType"] = "partId";
+    snapshotComponent["linkData"] = partIdString;
+    m_snapshot.components[componentIdString] = snapshotComponent;
+    
+    m_snapshot.rootComponent["children"] = componentIdString;
+    
+    std::vector<QString> nodeIdStrings;
+    nodeIdStrings.reserve(m_nodes.size());
+    for (const auto &it: m_nodes) {
+        auto nodeId = QUuid::createUuid();
+        auto nodeIdString = nodeId.toString();
+        std::map<QString, QString> snapshotNode;
+        snapshotNode["id"] = nodeIdString;
+        snapshotNode["x"] = QString::number(it.first.x());
+        snapshotNode["y"] = QString::number(it.first.y());
+        snapshotNode["z"] = QString::number(it.first.z());
+        snapshotNode["radius"] = QString::number(it.second);
+        snapshotNode["partId"] = partIdString;
+        m_snapshot.nodes[nodeIdString] = snapshotNode;
+        nodeIdStrings.push_back(nodeIdString);
+    }
+    
+    for (size_t i = 1; i < nodeIdStrings.size(); ++i) {
+        size_t h = i - 1;
+        auto edgeId = QUuid::createUuid();
+        auto edgeIdString = edgeId.toString();
+        std::map<QString, QString> snapshotEdge;
+        snapshotEdge["id"] = edgeIdString;
+        snapshotEdge["from"] = nodeIdStrings[h];
+        snapshotEdge["to"] = nodeIdStrings[i];
+        snapshotEdge["partId"] = partIdString;
+        m_snapshot.edges[edgeIdString] = snapshotEdge;
+    }
+}
+
diff --git a/src/contourtopartconverter.h b/src/contourtopartconverter.h
new file mode 100644
index 00000000..e9d904b9
--- /dev/null
+++ b/src/contourtopartconverter.h
@@ -0,0 +1,40 @@
+#ifndef DUST3D_CONTOUR_TO_PART_CONVERTER_H
+#define DUST3D_CONTOUR_TO_PART_CONVERTER_H
+#include <QObject>
+#include <QPolygonF>
+#include <QVector3D>
+#include <QVector2D>
+#include <set>
+#include "snapshot.h"
+
+class ContourToPartConverter : public QObject
+{
+    Q_OBJECT
+public:
+    ContourToPartConverter(const QPolygonF &mainProfile, const QPolygonF &sideProfile, const QSizeF &canvasSize);
+    const Snapshot &getSnapshot();
+signals:
+    void finished();
+public slots:
+    void process();
+private:
+    QPolygonF m_mainProfile;
+    QPolygonF m_sideProfile;
+    QSizeF m_canvasSize;
+    Snapshot m_snapshot;
+    static const float m_targetImageHeight;
+    static const float m_minEdgeLength;
+    static const float m_radiusEpsilon;
+    std::vector<std::pair<QVector3D, float>> m_nodes;
+    void convert();
+    void extractSkeleton(const QPolygonF &polygon,
+        std::vector<std::pair<QVector2D, float>> *skeleton);
+    int calculateNodeRadius(const QVector3D &node,
+        const QVector3D &direction,
+        const std::set<std::pair<int, int>> &black);
+    void nodesToSnapshot();
+    void smoothRadius(std::vector<std::pair<QVector2D, float>> *skeleton);
+    void optimizeNodes();
+};
+
+#endif
diff --git a/src/document.cpp b/src/document.cpp
index 23ba69d9..36254f47 100644
--- a/src/document.cpp
+++ b/src/document.cpp
@@ -19,6 +19,7 @@
 #include "scriptrunner.h"
 #include "mousepicker.h"
 #include "imageforever.h"
+#include "contourtopartconverter.h"
 
 unsigned long Document::m_maxSnapshot = 1000;
 
@@ -324,6 +325,28 @@ void Document::addNode(float x, float y, float z, float radius, QUuid fromNodeId
     createNode(QUuid::createUuid(), x, y, z, radius, fromNodeId);
 }
 
+void Document::addPartByPolygons(const QPolygonF &mainProfile, const QPolygonF &sideProfile, const QSizeF &canvasSize)
+{
+    if (mainProfile.empty() || sideProfile.empty())
+        return;
+    
+    QThread *thread = new QThread;
+    ContourToPartConverter *contourToPartConverter = new ContourToPartConverter(mainProfile, sideProfile, canvasSize);
+    contourToPartConverter->moveToThread(thread);
+    connect(thread, &QThread::started, contourToPartConverter, &ContourToPartConverter::process);
+    connect(contourToPartConverter, &ContourToPartConverter::finished, this, [=]() {
+        const auto &snapshot = contourToPartConverter->getSnapshot();
+        if (!snapshot.nodes.empty()) {
+            addFromSnapshot(snapshot, true);
+            saveSnapshot();
+        }
+        delete contourToPartConverter;
+    });
+    connect(contourToPartConverter, &ContourToPartConverter::finished, thread, &QThread::quit);
+    connect(thread, &QThread::finished, thread, &QThread::deleteLater);
+    thread->start();
+}
+
 void Document::addNodeWithId(QUuid nodeId, float x, float y, float z, float radius, QUuid fromNodeId)
 {
     createNode(nodeId, x, y, z, radius, fromNodeId);
@@ -1522,7 +1545,12 @@ void Document::addFromSnapshot(const Snapshot &snapshot, bool fromPaste)
         part.id = newUuid;
         oldNewIdMap[QUuid(partKv.first)] = part.id;
         part.name = valueOfKeyInMapOrEmpty(partKv.second, "name");
-        part.visible = isTrueValueString(valueOfKeyInMapOrEmpty(partKv.second, "visible"));
+        const auto &visibleIt = partKv.second.find("visible");
+        if (visibleIt != partKv.second.end()) {
+            part.visible = isTrueValueString(visibleIt->second);
+        } else {
+            part.visible = true;
+        }
         part.locked = isTrueValueString(valueOfKeyInMapOrEmpty(partKv.second, "locked"));
         part.subdived = isTrueValueString(valueOfKeyInMapOrEmpty(partKv.second, "subdived"));
         part.disabled = isTrueValueString(valueOfKeyInMapOrEmpty(partKv.second, "disabled"));
diff --git a/src/document.h b/src/document.h
index e1c140a0..ad420862 100644
--- a/src/document.h
+++ b/src/document.h
@@ -10,6 +10,7 @@
 #include <cmath>
 #include <algorithm>
 #include <QOpenGLWidget>
+#include <QPolygon>
 #include "snapshot.h"
 #include "meshloader.h"
 #include "meshgenerator.h"
@@ -567,6 +568,7 @@ public slots:
     void removeNode(QUuid nodeId);
     void removeEdge(QUuid edgeId);
     void removePart(QUuid partId);
+    void addPartByPolygons(const QPolygonF &mainProfile, const QPolygonF &sideProfile, const QSizeF &canvasSize);
     void addNodeWithId(QUuid nodeId, float x, float y, float z, float radius, QUuid fromNodeId);
     void addNode(float x, float y, float z, float radius, QUuid fromNodeId);
     void scaleNodeByAddRadius(QUuid nodeId, float amount);
diff --git a/src/documentwindow.cpp b/src/documentwindow.cpp
index 43bb2085..788005c9 100644
--- a/src/documentwindow.cpp
+++ b/src/documentwindow.cpp
@@ -160,6 +160,10 @@ DocumentWindow::DocumentWindow() :
     selectButton->setToolTip(tr("Select node on canvas"));
     Theme::initAwesomeButton(selectButton);
     
+    QPushButton *markerButton = new QPushButton(QChar(fa::edit));
+    markerButton->setToolTip(tr("Marker pen"));
+    Theme::initAwesomeButton(markerButton);
+    
     QPushButton *paintButton = new QPushButton(QChar(fa::paintbrush));
     paintButton->setToolTip(tr("Paint brush"));
     Theme::initAwesomeButton(paintButton);
@@ -240,6 +244,7 @@ DocumentWindow::DocumentWindow() :
 
     toolButtonLayout->addWidget(addButton);
     toolButtonLayout->addWidget(selectButton);
+    toolButtonLayout->addWidget(markerButton);
     toolButtonLayout->addWidget(paintButton);
     //toolButtonLayout->addWidget(dragButton);
     toolButtonLayout->addWidget(zoomInButton);
@@ -853,6 +858,10 @@ DocumentWindow::DocumentWindow() :
         m_document->setEditMode(SkeletonDocumentEditMode::Select);
     });
     
+    connect(markerButton, &QPushButton::clicked, [=]() {
+        m_document->setEditMode(SkeletonDocumentEditMode::Mark);
+    });
+    
     connect(paintButton, &QPushButton::clicked, [=]() {
         m_document->setEditMode(SkeletonDocumentEditMode::Paint);
     });
@@ -942,6 +951,7 @@ DocumentWindow::DocumentWindow() :
     connect(graphicsWidget, &SkeletonGraphicsWidget::setPartRoundState, m_document, &Document::setPartRoundState);
     connect(graphicsWidget, &SkeletonGraphicsWidget::setPartWrapState, m_document, &Document::setPartCutRotation);
     connect(graphicsWidget, &SkeletonGraphicsWidget::createGriddedPartsFromNodes, m_document, &Document::createGriddedPartsFromNodes);
+    connect(graphicsWidget, &SkeletonGraphicsWidget::addPartByPolygons, m_document, &Document::addPartByPolygons);
 
     connect(graphicsWidget, &SkeletonGraphicsWidget::setXlockState, m_document, &Document::setXlockState);
     connect(graphicsWidget, &SkeletonGraphicsWidget::setYlockState, m_document, &Document::setYlockState);
diff --git a/src/gridmeshbuilder.cpp b/src/gridmeshbuilder.cpp
index e924adfe..e10539c4 100644
--- a/src/gridmeshbuilder.cpp
+++ b/src/gridmeshbuilder.cpp
@@ -61,7 +61,7 @@ void GridMeshBuilder::splitCycleToPolylines(const std::vector<size_t> &cycle,
         size_t j = (i + 1) % cycle.size();
         QVector3D hi = m_nodeVertices[cycle[i]].position - m_nodeVertices[cycle[h]].position;
         QVector3D ij = m_nodeVertices[cycle[j]].position - m_nodeVertices[cycle[i]].position;
-        auto angle = angleBetweenVectors(hi, ij);
+        auto angle = degreesBetweenVectors(hi, ij);
         //qDebug() << "angle[" << i << "]:" << angle;
         if (angle >= m_polylineAngleChangeThreshold)
             cornerIndices.push_back(i);
diff --git a/src/imageskeletonextractor.cpp b/src/imageskeletonextractor.cpp
index f00a234a..085988d9 100644
--- a/src/imageskeletonextractor.cpp
+++ b/src/imageskeletonextractor.cpp
@@ -1,11 +1,12 @@
+#include <QDebug>
+#include <queue>
+#include <set>
 #include "imageskeletonextractor.h"
 
 // This is an implementation of the following paper:
 // <A Fast Parallel Algorithm for Thinning Digital Patterns>
 // T. Y. ZHANG and C. Y. SUEN
 
-const int ImageSkeletonExtractor::m_targetHeight = 256;
-
 ImageSkeletonExtractor::~ImageSkeletonExtractor()
 {
     delete m_image;
@@ -71,12 +72,34 @@ bool ImageSkeletonExtractor::secondSubiterationSatisfied(int i, int j)
     return true;
 }
 
+void ImageSkeletonExtractor::calculateAreaAndBlackPixels()
+{
+    m_area = 0;
+    m_blackPixels.clear();
+    for (int i = 1; i < (int)m_grayscaleImage->width() - 1; ++i) {
+        for (int j = 1; j < (int)m_grayscaleImage->height() - 1; ++j) {
+            if (isBlack(i, j)) {
+                ++m_area;
+                m_blackPixels.insert({i, j});
+            }
+        }
+    }
+}
+
+const std::set<std::pair<int, int>> &ImageSkeletonExtractor::getBlackPixels()
+{
+    return m_blackPixels;
+}
+
+int ImageSkeletonExtractor::getArea()
+{
+    return m_area;
+}
+
 void ImageSkeletonExtractor::extract()
 {
-    m_grayscaleImage = new QImage(m_image->convertToFormat(
-        QImage::Format_Grayscale8).scaled(
-            QSize(m_targetHeight, m_targetHeight), Qt::KeepAspectRatio));
-    
+    m_grayscaleImage = new QImage(m_image->convertToFormat(QImage::Format_Grayscale8));
+    calculateAreaAndBlackPixels();
     while (true) {
         std::vector<std::pair<int, int>> firstSatisfied;
         for (int i = 1; i < (int)m_grayscaleImage->width() - 1; ++i) {
@@ -98,7 +121,140 @@ void ImageSkeletonExtractor::extract()
             setWhite(it.first, it.second);
         if (firstSatisfied.empty() && secondSatisfied.empty())
             break;
-        printf("firstSatisfied:%d\r\n", firstSatisfied.size());
-        printf("secondSatisfied:%d\r\n", secondSatisfied.size());
+    }
+}
+
+void ImageSkeletonExtractor::getSkeleton(std::vector<std::pair<int, int>> *skeleton)
+{
+    if (nullptr == m_grayscaleImage)
+        return;
+    
+    std::map<std::pair<int, int>, std::vector<std::pair<int, int>>> links;
+    for (int i = 1; i < (int)m_grayscaleImage->width() - 1; ++i) {
+        for (int j = 1; j < (int)m_grayscaleImage->height() - 1; ++j) {
+            if (!isBlack(i, j))
+                continue;
+            auto ij = std::make_pair(i, j);
+            auto p2 = std::make_pair(i + neighborOffsets[P2].first, j + neighborOffsets[P2].second);
+            bool hasP3 = true;
+            bool hasP5 = true;
+            bool hasP7 = true;
+            bool hasP9 = true;
+            if (isBlack(p2.first, p2.second)) {
+                links[ij].push_back(p2);
+                hasP3 = false;
+                hasP9 = false;
+            }
+            auto p4 = std::make_pair(i + neighborOffsets[P4].first, j + neighborOffsets[P4].second);
+            if (isBlack(p4.first, p4.second)) {
+                links[ij].push_back(p4);
+                hasP3 = false;
+                hasP5 = false;
+            }
+            auto p6 = std::make_pair(i + neighborOffsets[P6].first, j + neighborOffsets[P6].second);
+            if (isBlack(p6.first, p6.second)) {
+                links[ij].push_back(p6);
+                hasP5 = false;
+                hasP7 = false;
+            }
+            auto p8 = std::make_pair(i + neighborOffsets[P8].first, j + neighborOffsets[P8].second);
+            if (isBlack(p8.first, p8.second)) {
+                links[ij].push_back(p8);
+                hasP7 = false;
+                hasP9 = false;
+            }
+            if (hasP3) {
+                auto p3 = std::make_pair(i + neighborOffsets[P3].first, j + neighborOffsets[P3].second);
+                if (isBlack(p3.first, p3.second)) {
+                    links[ij].push_back(p3);
+                }
+            }
+            if (hasP5) {
+                auto p5 = std::make_pair(i + neighborOffsets[P5].first, j + neighborOffsets[P5].second);
+                if (isBlack(p5.first, p5.second)) {
+                    links[ij].push_back(p5);
+                }
+            }
+            if (hasP7) {
+                auto p7 = std::make_pair(i + neighborOffsets[P7].first, j + neighborOffsets[P7].second);
+                if (isBlack(p7.first, p7.second)) {
+                    links[ij].push_back(p7);
+                }
+            }
+            if (hasP9) {
+                auto p9 = std::make_pair(i + neighborOffsets[P9].first, j + neighborOffsets[P9].second);
+                if (isBlack(p9.first, p9.second)) {
+                    links[ij].push_back(p9);
+                }
+            }
+        }
+    }
+
+    auto calculateRouteLength = [&](const std::pair<int, int> &branch, const std::pair<int, int> &start) {
+        std::set<std::pair<int, int>> visited;
+        visited.insert(branch);
+        std::queue<std::pair<int, int>> waitPoints;
+        waitPoints.push(start);
+        size_t addLength = 0;
+        while (!waitPoints.empty()) {
+            auto point = waitPoints.front();
+            waitPoints.pop();
+            if (visited.find(point) != visited.end())
+                continue;
+            visited.insert(point);
+            auto findLink = links.find(point);
+            if (findLink == links.end())
+                break;
+            if (findLink->second.size() > 2) {
+                addLength = links.size(); // This will make sure the branch node is not been removed
+                break;
+            }
+            for (const auto &it: findLink->second) {
+                if (visited.find(it) != visited.end())
+                    continue;
+                waitPoints.push(it);
+            }
+        }
+        return visited.size() + addLength;
+    };
+    for (auto &it: links) {
+        if (it.second.size() > 2) {
+            std::vector<std::pair<std::pair<int, int>, size_t>> routes;
+            routes.reserve(it.second.size());
+            for (size_t i = 0; i < it.second.size(); ++i) {
+                routes.push_back(std::make_pair(it.second[i], calculateRouteLength(it.first, it.second[i])));
+            }
+            std::sort(routes.begin(), routes.end(), [](const std::pair<std::pair<int, int>, size_t> &first,
+                    const std::pair<std::pair<int, int>, size_t> &second) {
+                return first.second < second.second;
+            });
+            it.second = std::vector<std::pair<int, int>> {routes[routes.size() - 2].first,
+                routes[routes.size() - 1].first};
+        }
+    }
+    
+    std::queue<std::pair<int, int>> waitPoints;
+    for (const auto &it: links) {
+        if (1 == it.second.size()) {
+            waitPoints.push(it.first);
+            break;
+        }
+    }
+    std::set<std::pair<int, int>> visited;
+    while (!waitPoints.empty()) {
+        auto point = waitPoints.front();
+        waitPoints.pop();
+        if (visited.find(point) != visited.end())
+            continue;
+        visited.insert(point);
+        skeleton->push_back(point);
+        auto findLink = links.find(point);
+        if (findLink == links.end())
+            break;
+        for (const auto &it: findLink->second) {
+            if (visited.find(it) != visited.end())
+                continue;
+            waitPoints.push(it);
+        }
     }
 }
diff --git a/src/imageskeletonextractor.h b/src/imageskeletonextractor.h
index 8792375a..2cc85e89 100644
--- a/src/imageskeletonextractor.h
+++ b/src/imageskeletonextractor.h
@@ -3,6 +3,7 @@
 #include <QImage>
 #include <QObject>
 #include <vector>
+#include <set>
 
 class ImageSkeletonExtractor : QObject
 {
@@ -33,10 +34,14 @@ public:
     void setImage(QImage *image);
     void extract();
     QImage *takeResultGrayscaleImage();
+    void getSkeleton(std::vector<std::pair<int, int>> *skeleton);
+    int getArea();
+    const std::set<std::pair<int, int>> &getBlackPixels();
 private:
     QImage *m_image = nullptr;
     QImage *m_grayscaleImage = nullptr;
-    static const int m_targetHeight;
+    int m_area = 0;
+    std::set<std::pair<int, int>> m_blackPixels;
     
     bool isBlack(int i, int j)
     {
@@ -78,6 +83,7 @@ private:
     
     bool firstSubiterationSatisfied(int i, int j);
     bool secondSubiterationSatisfied(int i, int j);
+    void calculateAreaAndBlackPixels();
 };
 
 #endif
diff --git a/src/main.cpp b/src/main.cpp
index 1882165b..40cbca34 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -19,10 +19,10 @@ int main(int argc, char ** argv)
     if (translator.load(QLocale(), QLatin1String("dust3d"), QLatin1String("_"), QLatin1String(":/languages")))
         app.installTranslator(&translator);
     
-    QSurfaceFormat format = QSurfaceFormat::defaultFormat();
-    format.setProfile(QSurfaceFormat::OpenGLContextProfile::CoreProfile);
-    format.setVersion(3, 3);
-    QSurfaceFormat::setDefaultFormat(format);
+    //QSurfaceFormat format = QSurfaceFormat::defaultFormat();
+    //format.setProfile(QSurfaceFormat::OpenGLContextProfile::CoreProfile);
+    //format.setVersion(3, 3);
+    //QSurfaceFormat::setDefaultFormat(format);
     
     // QuantumCD/Qt 5 Dark Fusion Palette
     // https://gist.github.com/QuantumCD/6245215
diff --git a/src/materialpreviewsgenerator.cpp b/src/materialpreviewsgenerator.cpp
index 585c7e31..3cb3e94e 100644
--- a/src/materialpreviewsgenerator.cpp
+++ b/src/materialpreviewsgenerator.cpp
@@ -73,35 +73,37 @@ void MaterialPreviewsGenerator::generate()
         delete poseProcessor;
     }
     
-    for (const auto &material: m_materials) {
-        TextureGenerator *textureGenerator = new TextureGenerator(*outcome);
-        for (const auto &layer: material.second) {
-            for (const auto &mapItem: layer.maps) {
-                const QImage *image = ImageForever::get(mapItem.imageId);
-                if (nullptr == image)
-                    continue;
-                for (const auto &partId: partIds) {
-                    if (TextureType::BaseColor == mapItem.forWhat)
-                        textureGenerator->addPartColorMap(partId, image, layer.tileScale);
-                    else if (TextureType::Normal == mapItem.forWhat)
-                        textureGenerator->addPartNormalMap(partId, image, layer.tileScale);
-                    else if (TextureType::Metalness == mapItem.forWhat)
-                        textureGenerator->addPartMetalnessMap(partId, image, layer.tileScale);
-                    else if (TextureType::Roughness == mapItem.forWhat)
-                        textureGenerator->addPartRoughnessMap(partId, image, layer.tileScale);
-                    else if (TextureType::AmbientOcclusion == mapItem.forWhat)
-                        textureGenerator->addPartAmbientOcclusionMap(partId, image, layer.tileScale);
+    if (nullptr != outcome) {
+        for (const auto &material: m_materials) {
+            TextureGenerator *textureGenerator = new TextureGenerator(*outcome);
+            for (const auto &layer: material.second) {
+                for (const auto &mapItem: layer.maps) {
+                    const QImage *image = ImageForever::get(mapItem.imageId);
+                    if (nullptr == image)
+                        continue;
+                    for (const auto &partId: partIds) {
+                        if (TextureType::BaseColor == mapItem.forWhat)
+                            textureGenerator->addPartColorMap(partId, image, layer.tileScale);
+                        else if (TextureType::Normal == mapItem.forWhat)
+                            textureGenerator->addPartNormalMap(partId, image, layer.tileScale);
+                        else if (TextureType::Metalness == mapItem.forWhat)
+                            textureGenerator->addPartMetalnessMap(partId, image, layer.tileScale);
+                        else if (TextureType::Roughness == mapItem.forWhat)
+                            textureGenerator->addPartRoughnessMap(partId, image, layer.tileScale);
+                        else if (TextureType::AmbientOcclusion == mapItem.forWhat)
+                            textureGenerator->addPartAmbientOcclusionMap(partId, image, layer.tileScale);
+                    }
                 }
             }
+            textureGenerator->generate();
+            MeshLoader *texturedResultMesh = textureGenerator->takeResultMesh();
+            if (nullptr != texturedResultMesh) {
+                m_previews[material.first] = new MeshLoader(*texturedResultMesh);
+                m_generatedMaterialIds.insert(material.first);
+                delete texturedResultMesh;
+            }
+            delete textureGenerator;
         }
-        textureGenerator->generate();
-        MeshLoader *texturedResultMesh = textureGenerator->takeResultMesh();
-        if (nullptr != texturedResultMesh) {
-            m_previews[material.first] = new MeshLoader(*texturedResultMesh);
-            m_generatedMaterialIds.insert(material.first);
-            delete texturedResultMesh;
-        }
-        delete textureGenerator;
     }
     
     delete outcome;
diff --git a/src/meshresultpostprocessor.cpp b/src/meshresultpostprocessor.cpp
index 9e564425..496bb15b 100644
--- a/src/meshresultpostprocessor.cpp
+++ b/src/meshresultpostprocessor.cpp
@@ -23,6 +23,9 @@ Outcome *MeshResultPostProcessor::takePostProcessedOutcome()
 
 void MeshResultPostProcessor::poseProcess()
 {
+#ifndef NDEBUG
+    return;
+#endif
     if (!m_outcome->nodes.empty()) {
         {
             std::vector<std::vector<QVector2D>> triangleVertexUvs;
diff --git a/src/meshwrapper.cpp b/src/meshwrapper.cpp
index 7edf8c24..c7905d73 100644
--- a/src/meshwrapper.cpp
+++ b/src/meshwrapper.cpp
@@ -151,7 +151,7 @@ float MeshWrapper::angleOfBaseFaceAndPoint(size_t itemIndex, size_t vertexIndex)
     auto vd1 = calculateFaceVector(item.p1, item.p2, item.baseNormal);
     auto normal = QVector3D::normal(v2.position, v1.position, vp.position);
     auto vd2 = calculateFaceVector(item.p1, item.p2, normal);
-    return angleBetweenVectors(vd2, vd1);
+    return degreesBetweenVectors(vd2, vd1);
 }
 
 std::pair<size_t, bool> MeshWrapper::findBestVertexOnTheLeft(size_t itemIndex)
diff --git a/src/shortcuts.cpp b/src/shortcuts.cpp
index 1f1111eb..4fff7b6e 100644
--- a/src/shortcuts.cpp
+++ b/src/shortcuts.cpp
@@ -15,6 +15,7 @@ void initShortCuts(QWidget *widget, SkeletonGraphicsWidget *graphicsWidget)
     defineKey(Qt::Key_Delete, &SkeletonGraphicsWidget::shortcutDelete);
     defineKey(Qt::Key_Backspace, &SkeletonGraphicsWidget::shortcutDelete);
     defineKey(Qt::Key_A, &SkeletonGraphicsWidget::shortcutAddMode);
+    defineKey(Qt::Key_G, &SkeletonGraphicsWidget::shortcutMarkMode);
     defineKey(Qt::CTRL + Qt::Key_A, &SkeletonGraphicsWidget::shortcutSelectAll);
     defineKey(Qt::CTRL + Qt::Key_Z, &SkeletonGraphicsWidget::shortcutUndo);
     defineKey(Qt::CTRL + Qt::SHIFT + Qt::Key_Z, &SkeletonGraphicsWidget::shortcutRedo);
diff --git a/src/skeletondocument.h b/src/skeletondocument.h
index 1f709742..3d07ac71 100644
--- a/src/skeletondocument.h
+++ b/src/skeletondocument.h
@@ -337,6 +337,7 @@ enum class SkeletonDocumentEditMode
 {
     Add = 0,
     Select,
+    Mark,
     Paint,
     Drag,
     ZoomIn,
diff --git a/src/skeletongraphicswidget.cpp b/src/skeletongraphicswidget.cpp
index 6fcb7acb..b22feaca 100644
--- a/src/skeletongraphicswidget.cpp
+++ b/src/skeletongraphicswidget.cpp
@@ -9,6 +9,7 @@
 #include <QApplication>
 #include <QMatrix4x4>
 #include <queue>
+#include <QBitmap>
 #include "skeletongraphicswidget.h"
 #include "theme.h"
 #include "util.h"
@@ -31,7 +32,9 @@ SkeletonGraphicsWidget::SkeletonGraphicsWidget(const SkeletonDocument *document)
     m_lastAddedY(false),
     m_lastAddedZ(false),
     m_selectionItem(nullptr),
+    m_markerItem(nullptr),
     m_rangeSelectionStarted(false),
+    m_markerStarted(false),
     m_mouseEventFromSelf(false),
     m_moveHappened(false),
     m_lastRot(0),
@@ -79,6 +82,10 @@ SkeletonGraphicsWidget::SkeletonGraphicsWidget(const SkeletonDocument *document)
     m_selectionItem->hide();
     scene()->addItem(m_selectionItem);
     
+    m_markerItem = new SkeletonGraphicsMarkerItem();
+    m_markerItem->hide();
+    scene()->addItem(m_markerItem);
+    
     m_mainOriginItem = new SkeletonGraphicsOriginItem(SkeletonProfile::Main);
     m_mainOriginItem->setRotated(m_rotated);
     m_mainOriginItem->hide();
@@ -725,6 +732,13 @@ void SkeletonGraphicsWidget::updateCursor()
         case SkeletonDocumentEditMode::Select:
             setCursor(QCursor(Theme::awesome()->icon(fa::mousepointer).pixmap(Theme::toolIconFontSize, Theme::toolIconFontSize), Theme::toolIconFontSize / 5, 0));
             break;
+        case SkeletonDocumentEditMode::Mark: {
+                auto pixmap = Theme::awesome()->icon(fa::pencil).pixmap(Theme::toolIconFontSize, Theme::toolIconFontSize);
+                QPixmap replacedPixmap(pixmap.size());
+                replacedPixmap.fill(m_markerItem->color());
+                replacedPixmap.setMask(pixmap.createMaskFromColor(Qt::transparent));
+                setCursor(QCursor(replacedPixmap, Theme::toolIconFontSize / 5, Theme::toolIconFontSize * 4 / 5));
+            } break;
         case SkeletonDocumentEditMode::Paint:
             setCursor(QCursor(Theme::awesome()->icon(fa::paintbrush).pixmap(Theme::toolIconFontSize, Theme::toolIconFontSize)));
             break;
@@ -857,6 +871,16 @@ bool SkeletonGraphicsWidget::mouseMove(QMouseEvent *event)
         }
     }
     
+    if (SkeletonDocumentEditMode::Mark == m_document->editMode) {
+        if (m_markerStarted) {
+            QPointF mouseScenePos = mouseEventScenePos(event);
+            m_markerItem->addPoint(mouseScenePos);
+            if (!m_markerItem->isVisible())
+                m_markerItem->setVisible(true);
+            return true;
+        }
+    }
+    
     if (SkeletonDocumentEditMode::Select == m_document->editMode ||
             SkeletonDocumentEditMode::Add == m_document->editMode) {
         
@@ -1410,7 +1434,7 @@ void SkeletonGraphicsWidget::rotateAllMainProfileCounterclockwise90DegreeAlongOr
 bool SkeletonGraphicsWidget::mouseRelease(QMouseEvent *event)
 {
     if (event->button() == Qt::LeftButton) {
-        bool processed = m_dragStarted || m_moveStarted || m_rangeSelectionStarted;
+        bool processed = m_dragStarted || m_moveStarted || m_rangeSelectionStarted || m_markerStarted;
         if (m_dragStarted) {
             m_dragStarted = false;
             updateCursor();
@@ -1425,6 +1449,28 @@ bool SkeletonGraphicsWidget::mouseRelease(QMouseEvent *event)
             m_selectionItem->hide();
             m_rangeSelectionStarted = false;
         }
+        if (m_markerStarted) {
+            auto boundingBox = m_markerItem->polygon().boundingRect();
+            if (boundingBox.width() * boundingBox.height() > 4) {
+                const QPolygonF &previousPolygon = m_markerItem->previousPolygon();
+                if (previousPolygon.empty()) {
+                    m_markerItem->save();
+                } else {
+                    if (m_markerItem->isMainProfile()) {
+                        emit addPartByPolygons(m_markerItem->polygon(), previousPolygon, sceneRect().size());
+                    } else {
+                        emit addPartByPolygons(previousPolygon, m_markerItem->polygon(), sceneRect().size());
+                    }
+                    m_markerItem->reset();
+                }
+                m_markerItem->hide();
+                m_markerItem->toggleProfile();
+                updateCursor();
+            } else {
+                m_markerItem->clear();
+            }
+            m_markerStarted = false;
+        }
         return processed;
     }
     return false;
@@ -1567,6 +1613,11 @@ bool SkeletonGraphicsWidget::mousePress(QMouseEvent *event)
                 m_rangeSelectionStartPos = mouseEventScenePos(event);
                 m_rangeSelectionStarted = true;
             }
+        } else if (SkeletonDocumentEditMode::Mark == m_document->editMode) {
+            if (!m_markerStarted) {
+                m_markerItem->addPoint(mouseEventScenePos(event));
+                m_markerStarted = true;
+            }
         }
     }
     return false;
@@ -1686,6 +1737,11 @@ void SkeletonGraphicsWidget::shortcutAddMode()
     }
 }
 
+void SkeletonGraphicsWidget::shortcutMarkMode()
+{
+    emit setEditMode(SkeletonDocumentEditMode::Mark);
+}
+
 void SkeletonGraphicsWidget::shortcutUndo()
 {
     emit undo();
@@ -1777,7 +1833,8 @@ void SkeletonGraphicsWidget::shortcutZoomSelectedBy1()
 
 void SkeletonGraphicsWidget::shortcutRotateSelectedByMinus1()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode && hasSelection()) {
+    if ((SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) &&
+            hasSelection()) {
         rotateSelected(-1);
         emit groupOperationAdded();
     }
@@ -1785,7 +1842,8 @@ void SkeletonGraphicsWidget::shortcutRotateSelectedByMinus1()
 
 void SkeletonGraphicsWidget::shortcutRotateSelectedBy1()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode && hasSelection()) {
+    if ((SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) &&
+            hasSelection()) {
         rotateSelected(1);
         emit groupOperationAdded();
     }
@@ -1793,7 +1851,7 @@ void SkeletonGraphicsWidget::shortcutRotateSelectedBy1()
 
 void SkeletonGraphicsWidget::shortcutMoveSelectedToLeft()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode) {
+    if (SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) {
         if (m_checkedOriginItem) {
             moveCheckedOrigin(-1, 0);
             emit groupOperationAdded();
@@ -1806,7 +1864,7 @@ void SkeletonGraphicsWidget::shortcutMoveSelectedToLeft()
 
 void SkeletonGraphicsWidget::shortcutMoveSelectedToRight()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode) {
+    if (SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) {
         if (m_checkedOriginItem) {
             moveCheckedOrigin(1, 0);
             emit groupOperationAdded();
@@ -1819,7 +1877,7 @@ void SkeletonGraphicsWidget::shortcutMoveSelectedToRight()
 
 void SkeletonGraphicsWidget::shortcutMoveSelectedToUp()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode) {
+    if (SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) {
         if (m_checkedOriginItem) {
             moveCheckedOrigin(0, -1);
             emit groupOperationAdded();
@@ -1832,7 +1890,7 @@ void SkeletonGraphicsWidget::shortcutMoveSelectedToUp()
 
 void SkeletonGraphicsWidget::shortcutMoveSelectedToDown()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode) {
+    if (SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) {
         if (m_checkedOriginItem) {
             moveCheckedOrigin(0, 1);
             emit groupOperationAdded();
@@ -1845,7 +1903,8 @@ void SkeletonGraphicsWidget::shortcutMoveSelectedToDown()
 
 void SkeletonGraphicsWidget::shortcutScaleSelectedByMinus1()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode && hasSelection()) {
+    if ((SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) &&
+            hasSelection()) {
         scaleSelected(-1);
         emit groupOperationAdded();
     }
@@ -1853,7 +1912,8 @@ void SkeletonGraphicsWidget::shortcutScaleSelectedByMinus1()
 
 void SkeletonGraphicsWidget::shortcutScaleSelectedBy1()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode && hasSelection()) {
+    if ((SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) &&
+            hasSelection()) {
         scaleSelected(1);
         emit groupOperationAdded();
     }
@@ -1861,7 +1921,8 @@ void SkeletonGraphicsWidget::shortcutScaleSelectedBy1()
 
 void SkeletonGraphicsWidget::shortcutSwitchProfileOnSelected()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode && hasSelection()) {
+    if ((SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) &&
+            hasSelection()) {
         switchProfileOnRangeSelection();
     }
 }
@@ -1882,7 +1943,8 @@ void SkeletonGraphicsWidget::shortcutShowOrHideSelectedPart()
 
 void SkeletonGraphicsWidget::shortcutEnableOrDisableSelectedPart()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode && !m_lastCheckedPart.isNull()) {
+    if ((SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) &&
+            !m_lastCheckedPart.isNull()) {
         const SkeletonPart *part = m_document->findPart(m_lastCheckedPart);
         bool partDisabled = part && part->disabled;
         emit setPartDisableState(m_lastCheckedPart, !partDisabled);
@@ -1892,7 +1954,8 @@ void SkeletonGraphicsWidget::shortcutEnableOrDisableSelectedPart()
 
 void SkeletonGraphicsWidget::shortcutLockOrUnlockSelectedPart()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode && !m_lastCheckedPart.isNull()) {
+    if ((SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) &&
+            !m_lastCheckedPart.isNull()) {
         const SkeletonPart *part = m_document->findPart(m_lastCheckedPart);
         bool partLocked = part && part->locked;
         emit setPartLockState(m_lastCheckedPart, !partLocked);
@@ -1902,7 +1965,8 @@ void SkeletonGraphicsWidget::shortcutLockOrUnlockSelectedPart()
 
 void SkeletonGraphicsWidget::shortcutXmirrorOnOrOffSelectedPart()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode && !m_lastCheckedPart.isNull()) {
+    if ((SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) &&
+            !m_lastCheckedPart.isNull()) {
         const SkeletonPart *part = m_document->findPart(m_lastCheckedPart);
         bool partXmirrored = part && part->xMirrored;
         emit setPartXmirrorState(m_lastCheckedPart, !partXmirrored);
@@ -1912,7 +1976,8 @@ void SkeletonGraphicsWidget::shortcutXmirrorOnOrOffSelectedPart()
 
 void SkeletonGraphicsWidget::shortcutSubdivedOrNotSelectedPart()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode && !m_lastCheckedPart.isNull()) {
+    if ((SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) &&
+            !m_lastCheckedPart.isNull()) {
         const SkeletonPart *part = m_document->findPart(m_lastCheckedPart);
         bool partSubdived = part && part->subdived;
         emit setPartSubdivState(m_lastCheckedPart, !partSubdived);
@@ -1922,7 +1987,8 @@ void SkeletonGraphicsWidget::shortcutSubdivedOrNotSelectedPart()
 
 void SkeletonGraphicsWidget::shortcutChamferedOrNotSelectedPart()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode && !m_lastCheckedPart.isNull()) {
+    if ((SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) &&
+            !m_lastCheckedPart.isNull()) {
         const SkeletonPart *part = m_document->findPart(m_lastCheckedPart);
         bool partChamfered = part && part->chamfered;
         emit setPartChamferState(m_lastCheckedPart, !partChamfered);
@@ -1937,7 +2003,8 @@ void SkeletonGraphicsWidget::shortcutSelectAll()
 
 void SkeletonGraphicsWidget::shortcutRoundEndOrNotSelectedPart()
 {
-    if (SkeletonDocumentEditMode::Select == m_document->editMode && !m_lastCheckedPart.isNull()) {
+    if ((SkeletonDocumentEditMode::Select == m_document->editMode || SkeletonDocumentEditMode::Mark == m_document->editMode) &&
+            !m_lastCheckedPart.isNull()) {
         const SkeletonPart *part = m_document->findPart(m_lastCheckedPart);
         bool partRounded = part && part->rounded;
         emit setPartRoundState(m_lastCheckedPart, !partRounded);
diff --git a/src/skeletongraphicswidget.h b/src/skeletongraphicswidget.h
index 9cd9fc3b..0c6c62e3 100644
--- a/src/skeletongraphicswidget.h
+++ b/src/skeletongraphicswidget.h
@@ -124,6 +124,68 @@ public:
     }
 };
 
+class SkeletonGraphicsMarkerItem : public QGraphicsPolygonItem
+{
+public:
+    SkeletonGraphicsMarkerItem()
+    {
+        updateAppearance();
+    }
+    void addPoint(const QPointF &point)
+    {
+        m_polygon.append(point);
+        setPolygon(m_polygon);
+    }
+    void clear()
+    {
+        m_polygon.clear();
+        setPolygon(m_polygon);
+    }
+    QColor color()
+    {
+        return m_mainProfile ? Theme::red : Theme::green;
+    }
+    bool isMainProfile()
+    {
+        return m_mainProfile;
+    }
+    void toggleProfile()
+    {
+        m_mainProfile = !m_mainProfile;
+        updateAppearance();
+    }
+    void save()
+    {
+        m_previousPolygon = m_polygon;
+        clear();
+    }
+    const QPolygonF &previousPolygon()
+    {
+        return m_previousPolygon;
+    }
+    const QPolygonF &polygon()
+    {
+        return m_polygon;
+    }
+    void reset()
+    {
+        m_previousPolygon.clear();
+        clear();
+    }
+private:
+    QPolygonF m_polygon;
+    QPolygonF m_previousPolygon;
+    bool m_mainProfile = true;
+    void updateAppearance()
+    {
+        QColor penColor(color());
+        QPen pen(penColor);
+        pen.setWidth(2);
+        pen.setStyle(Qt::SolidLine);
+        setPen(pen);
+    }
+};
+
 class SkeletonGraphicsNodeItem : public QGraphicsEllipseItem
 {
 public:
@@ -441,6 +503,7 @@ signals:
     void shortcutToggleFlatShading();
     void shortcutToggleRotation();
     void createGriddedPartsFromNodes(const std::set<QUuid> &nodeIds);
+    void addPartByPolygons(const QPolygonF &mainProfile, const QPolygonF &sideProfile, const QSizeF &canvasSize);
 public:
     SkeletonGraphicsWidget(const SkeletonDocument *document);
     std::map<QUuid, std::pair<SkeletonGraphicsNodeItem *, SkeletonGraphicsNodeItem *>> nodeItemMap;
@@ -544,6 +607,7 @@ public slots:
     void createWrapParts();
     void shortcutDelete();
     void shortcutAddMode();
+    void shortcutMarkMode();
     void shortcutUndo();
     void shortcutRedo();
     void shortcutXlock();
@@ -618,7 +682,9 @@ private: //need initalize
     float m_lastAddedY;
     float m_lastAddedZ;
     SkeletonGraphicsSelectionItem *m_selectionItem;
+    SkeletonGraphicsMarkerItem *m_markerItem;
     bool m_rangeSelectionStarted;
+    bool m_markerStarted;
     bool m_mouseEventFromSelf;
     bool m_moveHappened;
     int m_lastRot;
diff --git a/src/strokemodifier.cpp b/src/strokemodifier.cpp
index a69aeb00..8d487231 100644
--- a/src/strokemodifier.cpp
+++ b/src/strokemodifier.cpp
@@ -155,8 +155,10 @@ void StrokeModifier::finalize()
         size_t newInsertNum = currentEdgeLength / targetEdgeLength;
         if (newInsertNum < 1)
             newInsertNum = 1;
-        if (newInsertNum > 100)
+        if (newInsertNum > 100) {
+            addEdge(edge.firstNodeIndex, edge.secondNodeIndex);
             continue;
+        }
         float stepFactor = 1.0 / (newInsertNum + 1);
         std::vector<size_t> nodeIndices;
         nodeIndices.push_back(edge.firstNodeIndex);
diff --git a/src/util.cpp b/src/util.cpp
index 8fc3b42b..382320a3 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -82,7 +82,7 @@ float radianBetweenVectors(const QVector3D &first, const QVector3D &second)
     return std::acos(QVector3D::dotProduct(first.normalized(), second.normalized()));
 };
 
-float angleBetweenVectors(const QVector3D &first, const QVector3D &second)
+float degreesBetweenVectors(const QVector3D &first, const QVector3D &second)
 {
     return radianBetweenVectors(first, second) * 180.0 / M_PI;
 }
@@ -160,9 +160,9 @@ void angleSmooth(const std::vector<QVector3D> &vertices,
         const auto &v2 = vertices[sourceTriangle[1]];
         const auto &v3 = vertices[sourceTriangle[2]];
         float area = areaOfTriangle(v1, v2, v3);
-        float angles[] = {angleBetweenVectors(v2-v1, v3-v1),
-            angleBetweenVectors(v1-v2, v3-v2),
-            angleBetweenVectors(v1-v3, v2-v3)};
+        float angles[] = {degreesBetweenVectors(v2-v1, v3-v1),
+            degreesBetweenVectors(v1-v2, v3-v2),
+            degreesBetweenVectors(v1-v3, v2-v3)};
         for (int i = 0; i < 3; ++i) {
             if (sourceTriangle[i] >= vertices.size()) {
                 qDebug() << "Invalid vertex index" << sourceTriangle[i] << "vertices size" << vertices.size();
@@ -183,7 +183,7 @@ void angleSmooth(const std::vector<QVector3D> &vertices,
                 float degrees = 0;
                 auto findDegreesResult = degreesBetweenFacesMap.find({triangleVertex.first, otherTriangleVertex.first});
                 if (findDegreesResult == degreesBetweenFacesMap.end()) {
-                    degrees = angleBetweenVectors(triangleNormals[triangleVertex.first], triangleNormals[otherTriangleVertex.first]);
+                    degrees = degreesBetweenVectors(triangleNormals[triangleVertex.first], triangleNormals[otherTriangleVertex.first]);
                     degreesBetweenFacesMap.insert({{triangleVertex.first, otherTriangleVertex.first}, degrees});
                     degreesBetweenFacesMap.insert({{otherTriangleVertex.first, triangleVertex.first}, degrees});
                 } else {
diff --git a/src/util.h b/src/util.h
index 36c98fed..00e0e4ac 100644
--- a/src/util.h
+++ b/src/util.h
@@ -23,7 +23,7 @@ QVector3D projectLineOnPlane(QVector3D line, QVector3D planeNormal);
 QString unifiedWindowTitle(const QString &text);
 QQuaternion quaternionOvershootSlerp(const QQuaternion &q0, const QQuaternion &q1, float t);
 float radianBetweenVectors(const QVector3D &first, const QVector3D &second);
-float angleBetweenVectors(const QVector3D &first, const QVector3D &second);
+float degreesBetweenVectors(const QVector3D &first, const QVector3D &second);
 float areaOfTriangle(const QVector3D &a, const QVector3D &b, const QVector3D &c);
 QQuaternion eulerAnglesToQuaternion(double pitch, double yaw, double roll);
 void quaternionToEulerAngles(const QQuaternion &q, double *pitch, double *yaw, double *roll);