diff --git a/qt/mainwindow.cpp b/qt/mainwindow.cpp
index e526d6a..61dbf0f 100644
--- a/qt/mainwindow.cpp
+++ b/qt/mainwindow.cpp
@@ -4,16 +4,12 @@
 #include <qdebug.h>
 #include <QMessageBox>
 
-#define BLACK 0xFF000000
-#define RED   0xFFFF0000
-#define WHITE 0xFFFFFFFF
-#define BLUE  0xFF0000FF
-
 MainWindow::MainWindow(QWidget *parent) :
     QMainWindow(parent),
     ui(new Ui::MainWindow)
 {
     ui->setupUi(this);
+    ui->graphicsView->setScene(&scene);
 }
 
 MainWindow::~MainWindow()
@@ -27,12 +23,11 @@ void MainWindow::on_pushLoad_clicked()
     if (filename.isNull()) return;
     QFileInfo pathInfo(filename);
     if (!vdata.load(pathInfo.path(), pathInfo.fileName())) {
-        QMessageBox("Error", "Error loading data");
+        qDebug() << "Error loading data";
     } else {
-        ui->sliderPosition->setMaximum(vdata.getDimZ());
+        ui->sliderPosition->setMaximum(vdata.getDimZ()-1);
         ui->sliderPosition->setValue(vdata.getDimZ()/2);
     }
-
 }
 
 /*
@@ -134,7 +129,31 @@ void MainWindow::floodfill(QImage &img)
 void MainWindow::on_sliderPosition_valueChanged(int value)
 {
     QPixmap pixmap;
+    if (ui->checkThreshold->checkState() != Qt::Unchecked) {
+        int threshold = ui->sliderThreshold->value();
+        QImage *img = new QImage(*vdata.getSlice(value));
+        for (int x = 0; x < img->width(); ++x) {
+            for (int y = 0; y < img->height(); ++y) {
+                img->setPixel(x,y, ((img->pixel(x,y) & 0xFF) > threshold) ? 255 : 0);
+            }
+        }
+        pixmap.convertFromImage(*img);
+        delete img;
+    } else {
+        pixmap.convertFromImage(*vdata.getSlice(value));
+    }
     scene.clear();
-    pixmap.convertFromImage(image);
     scene.addPixmap(pixmap);
 }
+
+void MainWindow::on_sliderThreshold_valueChanged(int value)
+{
+    if (ui->checkThreshold->checkState() != Qt::Unchecked) {
+        on_sliderPosition_valueChanged(ui->sliderPosition->value());
+    }
+}
+
+void MainWindow::on_checkThreshold_clicked()
+{
+    on_sliderPosition_valueChanged(ui->sliderPosition->value());
+}
diff --git a/qt/mainwindow.h b/qt/mainwindow.h
index 0992c41..7248f77 100644
--- a/qt/mainwindow.h
+++ b/qt/mainwindow.h
@@ -22,10 +22,13 @@ private slots:
 
     void on_sliderPosition_valueChanged(int value);
 
+    void on_sliderThreshold_valueChanged(int value);
+
+    void on_checkThreshold_clicked();
+
 private:
     Ui::MainWindow *ui;
     VoxelData vdata;
-    QImage img;
     QGraphicsScene scene;
 };
 
diff --git a/qt/mainwindow.ui b/qt/mainwindow.ui
index 8a2330c..76410a2 100644
--- a/qt/mainwindow.ui
+++ b/qt/mainwindow.ui
@@ -44,7 +44,7 @@
     <property name="geometry">
      <rect>
       <x>530</x>
-      <y>330</y>
+      <y>350</y>
       <width>141</width>
       <height>20</height>
      </rect>
@@ -72,45 +72,6 @@
      <string>Save</string>
     </property>
    </widget>
-   <widget class="QPushButton" name="pushAxis1">
-    <property name="geometry">
-     <rect>
-      <x>530</x>
-      <y>160</y>
-      <width>41</width>
-      <height>31</height>
-     </rect>
-    </property>
-    <property name="text">
-     <string>A-P</string>
-    </property>
-   </widget>
-   <widget class="QPushButton" name="pushAxis2">
-    <property name="geometry">
-     <rect>
-      <x>580</x>
-      <y>160</y>
-      <width>41</width>
-      <height>31</height>
-     </rect>
-    </property>
-    <property name="text">
-     <string>D-V</string>
-    </property>
-   </widget>
-   <widget class="QPushButton" name="pushAxis3">
-    <property name="geometry">
-     <rect>
-      <x>630</x>
-      <y>160</y>
-      <width>41</width>
-      <height>31</height>
-     </rect>
-    </property>
-    <property name="text">
-     <string>L-R</string>
-    </property>
-   </widget>
    <widget class="QSlider" name="sliderPosition">
     <property name="geometry">
      <rect>
@@ -159,7 +120,7 @@
      <number>0</number>
     </property>
    </widget>
-   <widget class="QProgressBar" name="progressLoad_2">
+   <widget class="QProgressBar" name="progressSave">
     <property name="geometry">
      <rect>
       <x>530</x>
@@ -172,6 +133,35 @@
      <number>0</number>
     </property>
    </widget>
+   <widget class="QLabel" name="labelSlice">
+    <property name="geometry">
+     <rect>
+      <x>530</x>
+      <y>180</y>
+      <width>141</width>
+      <height>21</height>
+     </rect>
+    </property>
+    <property name="text">
+     <string>Slice:</string>
+    </property>
+    <property name="alignment">
+     <set>Qt::AlignCenter</set>
+    </property>
+   </widget>
+   <widget class="QCheckBox" name="checkThreshold">
+    <property name="geometry">
+     <rect>
+      <x>530</x>
+      <y>330</y>
+      <width>141</width>
+      <height>20</height>
+     </rect>
+    </property>
+    <property name="text">
+     <string>Active</string>
+    </property>
+   </widget>
   </widget>
  </widget>
  <layoutdefault spacing="6" margin="11"/>
diff --git a/qt/voxeldata.cpp b/qt/voxeldata.cpp
index 8a1c8da..6a1bdea 100644
--- a/qt/voxeldata.cpp
+++ b/qt/voxeldata.cpp
@@ -6,28 +6,23 @@
 
 bool VoxelData::load(QString path, QString filename)
 {
+    data.clear();
     qDebug() << "Processing " + path + "/" + filename + " ...";
     QFile file(path + "/" + filename);
     if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
         return false;
     QTextStream in(&file);
-    int z = 0;
-    data = new VOXELDATA[512*512*512];
     while (!in.atEnd()) {
         QString line = in.readLine();
-        QImage img;
         qDebug() << "Loading " + line + " ...";
-        img.load(path + "/" + line);
-        dimx = img.width();
-        dimy = img.height();
-        for (int x = 0; x < dimx; ++x) {
-            for (int y = 0; y < dimy; ++y) {
-                data[ x + y*512 + z*512*512] = img.pixel(x,y) & 0xFF;
-            }
-        }
-        z++;
+        data.push_back(new QImage(path + "/" + line));
     }
-    dimz = z;
+    dimz = data.size();
     file.close();
     return true;
 }
+
+const QImage *VoxelData::getSlice(int z)
+{
+    return data[z];
+}
diff --git a/qt/voxeldata.h b/qt/voxeldata.h
index 82b4126..c1dfd49 100644
--- a/qt/voxeldata.h
+++ b/qt/voxeldata.h
@@ -2,8 +2,8 @@
 #define VOXELDATA_H
 
 #include <QString>
-
-#define VOXELDATA unsigned char
+#include <QImage>
+#include <QVector>
 
 class VoxelData
 {
@@ -12,9 +12,10 @@ public:
     inline int getDimY() { return dimy; }
     inline int getDimZ() { return dimz; }
     bool load(QString path, QString filename);
+    const QImage *getSlice(int z);
 private:
     int dimx, dimy, dimz;
-    VOXELDATA *data;
+    QVector<QImage *> data;
 };
 
 #endif