diff --git a/src/Mod/CAM/PathSimulator/AppGL/DlgCAMSimulator.cpp b/src/Mod/CAM/PathSimulator/AppGL/DlgCAMSimulator.cpp
index 5b923a8711..3b04b13118 100644
--- a/src/Mod/CAM/PathSimulator/AppGL/DlgCAMSimulator.cpp
+++ b/src/Mod/CAM/PathSimulator/AppGL/DlgCAMSimulator.cpp
@@ -238,10 +238,10 @@ void DlgCAMSimulator::startSimulation(const Part::TopoShape& stock, float qualit
 
 void DlgCAMSimulator::initialize()
 {
-    mMillSimulator->InitSimulation(mQuality);
-
     const qreal retinaScale = devicePixelRatio();
-    glViewport(0, 0, width() * retinaScale, height() * retinaScale);
+    mMillSimulator->InitSimulation(mQuality, retinaScale);
+
+    glViewport(0, 0, (int)(width() * retinaScale), (int)(height() * retinaScale));
 }
 
 void DlgCAMSimulator::checkInitialization()
diff --git a/src/Mod/CAM/PathSimulator/AppGL/MillSimulation.cpp b/src/Mod/CAM/PathSimulator/AppGL/MillSimulation.cpp
index 94b8b3f6e9..bccc15c7ac 100644
--- a/src/Mod/CAM/PathSimulator/AppGL/MillSimulation.cpp
+++ b/src/Mod/CAM/PathSimulator/AppGL/MillSimulation.cpp
@@ -89,7 +89,7 @@ void MillSimulation::SimNext()
     }
 }
 
-void MillSimulation::InitSimulation(float quality)
+void MillSimulation::InitSimulation(float quality, qreal devicePixelRatio)
 {
     ClearMillPathSegments();
     millPathLine.Clear();
@@ -121,7 +121,7 @@ void MillSimulation::InitSimulation(float quality)
     }
     mNPathSteps = (int)MillPathSegments.size();
     millPathLine.GenerateModel();
-    InitDisplay(quality);
+    InitDisplay(quality, devicePixelRatio);
 }
 
 EndMill* MillSimulation::GetTool(int toolId)
@@ -529,7 +529,7 @@ void MillSimulation::HandleGuiAction(eGuiItems actionItem, bool checked)
 }
 
 
-void MillSimulation::InitDisplay(float quality)
+void MillSimulation::InitDisplay(float quality, qreal devicePixelRatio)
 {
     // generate tools
     for (unsigned int i = 0; i < mToolTable.size(); i++) {
@@ -537,7 +537,7 @@ void MillSimulation::InitDisplay(float quality)
     }
 
     // init 3d display
-    simDisplay.InitGL();
+    simDisplay.InitGL(devicePixelRatio);
 
     // init gui elements
     guiDisplay.InitGui();
diff --git a/src/Mod/CAM/PathSimulator/AppGL/MillSimulation.h b/src/Mod/CAM/PathSimulator/AppGL/MillSimulation.h
index 55b81f553c..5c89031ea6 100644
--- a/src/Mod/CAM/PathSimulator/AppGL/MillSimulation.h
+++ b/src/Mod/CAM/PathSimulator/AppGL/MillSimulation.h
@@ -54,7 +54,7 @@ public:
     void ClearMillPathSegments();
     void Clear();
     void SimNext();
-    void InitSimulation(float quality);
+    void InitSimulation(float quality, qreal devicePixelRatio);
     void AddTool(EndMill* tool);
     void AddTool(const std::vector<float>& toolProfile, int toolid, float diameter);
     bool ToolExists(int toolid)
@@ -85,7 +85,7 @@ public:
 
 
 protected:
-    void InitDisplay(float quality);
+    void InitDisplay(float quality, qreal devicePixelRatio);
     void GlsimStart();
     void GlsimToolStep1(void);
     void GlsimToolStep2(void);
diff --git a/src/Mod/CAM/PathSimulator/AppGL/SimDisplay.cpp b/src/Mod/CAM/PathSimulator/AppGL/SimDisplay.cpp
index 1d097f8fd9..10713be58f 100644
--- a/src/Mod/CAM/PathSimulator/AppGL/SimDisplay.cpp
+++ b/src/Mod/CAM/PathSimulator/AppGL/SimDisplay.cpp
@@ -240,7 +240,7 @@ SimDisplay::~SimDisplay()
     CleanGL();
 }
 
-void SimDisplay::InitGL()
+void SimDisplay::InitGL(qreal devicePixelRatio)
 {
     if (displayInitiated) {
         return;
@@ -249,8 +249,9 @@ void SimDisplay::InitGL()
     // setup light object
     mlightObject.GenerateBoxStock(-0.5f, -0.5f, -0.5f, 1, 1, 1);
 
-    mWidth = gWindowSizeW;
-    mHeight = gWindowSizeH;
+    mDevicePixelRatio = devicePixelRatio;
+    mWidth = (int)(gWindowSizeW * mDevicePixelRatio);
+    mHeight = (int)(gWindowSizeH * mDevicePixelRatio);
     InitShaders();
     CreateDisplayFbos();
     CreateSsaoFbos();
@@ -550,8 +551,8 @@ void SimDisplay::UpdateEyeFactor(float factor)
 
 void SimDisplay::UpdateWindowScale()
 {
-    mWidth = gWindowSizeW;
-    mHeight = gWindowSizeH;
+    mWidth = (int)(gWindowSizeW * mDevicePixelRatio);
+    mHeight = (int)(gWindowSizeH * mDevicePixelRatio);
     glBindFramebuffer(GL_FRAMEBUFFER, mFbo);
     CleanFbos();
     CreateDisplayFbos();
diff --git a/src/Mod/CAM/PathSimulator/AppGL/SimDisplay.h b/src/Mod/CAM/PathSimulator/AppGL/SimDisplay.h
index bfcd5a1a24..a5b96f7881 100644
--- a/src/Mod/CAM/PathSimulator/AppGL/SimDisplay.h
+++ b/src/Mod/CAM/PathSimulator/AppGL/SimDisplay.h
@@ -47,7 +47,7 @@ class SimDisplay
 {
 public:
     ~SimDisplay();
-    void InitGL();
+    void InitGL(qreal devicePixelRatio);
     void CleanGL();
     void CleanFbos();
     void PrepareDisplay(vec3 objCenter);
@@ -108,6 +108,7 @@ protected:
     mat4x4 mMatLookAt;
     StockObject mlightObject;
 
+    qreal mDevicePixelRatio;
     int mWidth;
     int mHeight;