diff --git a/src/Mod/CAM/PathSimulator/AppGL/DlgCAMSimulator.cpp b/src/Mod/CAM/PathSimulator/AppGL/DlgCAMSimulator.cpp
index 3a61704d21..bff77663bf 100644
--- a/src/Mod/CAM/PathSimulator/AppGL/DlgCAMSimulator.cpp
+++ b/src/Mod/CAM/PathSimulator/AppGL/DlgCAMSimulator.cpp
@@ -24,17 +24,10 @@
 
 #include "DlgCAMSimulator.h"
 #include "MillSimulation.h"
-#include <QMatrix4x4>
-#include <QScreen>
 #include <QDateTime>
 #include <QSurfaceFormat>
-#include <QMouseEvent>
-#include <QWheelEvent>
 #include <QPoint>
 
-using namespace CAMSimulator;
-using namespace MillSim;
-
 QOpenGLContext* gOpenGlContext;
 
 using namespace MillSim;
@@ -214,6 +207,8 @@ DlgCAMSimulator* DlgCAMSimulator::GetInstance()
         QSurfaceFormat format;
         format.setSamples(16);
         format.setSwapInterval(2);
+        format.setDepthBufferSize(24);
+        format.setStencilBufferSize(8);
         mInstance = new DlgCAMSimulator();
         mInstance->setFormat(format);
         mInstance->resize(800, 600);
diff --git a/src/Mod/CAM/PathSimulator/AppGL/DlgCAMSimulator.h b/src/Mod/CAM/PathSimulator/AppGL/DlgCAMSimulator.h
index c3927be35d..a60b434860 100644
--- a/src/Mod/CAM/PathSimulator/AppGL/DlgCAMSimulator.h
+++ b/src/Mod/CAM/PathSimulator/AppGL/DlgCAMSimulator.h
@@ -25,11 +25,11 @@
 
 #include <QWindow>
 #include <QOpenGLExtraFunctions>
-
-#include <QtGui/qpainter.h>
 #include <QPainter>
-
-
+#include <QExposeEvent>
+#include <QResizeEvent>
+#include <QMouseEvent>
+#include <QOpenGLContext>
 
 namespace MillSim
 {
diff --git a/src/Mod/CAM/PathSimulator/AppGL/GCodeParser.cpp b/src/Mod/CAM/PathSimulator/AppGL/GCodeParser.cpp
index 3cb2f78332..4702f32838 100644
--- a/src/Mod/CAM/PathSimulator/AppGL/GCodeParser.cpp
+++ b/src/Mod/CAM/PathSimulator/AppGL/GCodeParser.cpp
@@ -222,9 +222,6 @@ bool GCodeParser::AddLine(const char* ptr)
             Operations.push_back(lastState);
             lastState.z = rPlane;
             Operations.push_back(lastState);
-            // restore original state
-            lastState.z = finalDepth;
-            lastState.cmd = eDril;
         }
         else {
             Operations.push_back(lastState);
diff --git a/src/Mod/CAM/PathSimulator/AppGL/MillSimulation.cpp b/src/Mod/CAM/PathSimulator/AppGL/MillSimulation.cpp
index 16223c2ae1..661df0a253 100644
--- a/src/Mod/CAM/PathSimulator/AppGL/MillSimulation.cpp
+++ b/src/Mod/CAM/PathSimulator/AppGL/MillSimulation.cpp
@@ -351,12 +351,12 @@ namespace MillSim {
     void MillSimulation::ProcessSim(unsigned int time_ms) {
 
         static int ancient = 0;
-        static int last = 0;
-        static int msec = 0;
+        static unsigned int last = 0;
+        static unsigned int msec = 0xFFFFFFFF;
         static int fps = 0;
         static int renderTime = 0;
 
-        last = msec;
+        last = msec == 0xFFFFFFFF ? time_ms : msec;
         msec = time_ms;
         if (mIsRotate) {
             mEyeRoration += (msec - last) / 4600.0f;
@@ -447,9 +447,9 @@ namespace MillSim {
     {
         mEyeRoration += rotStep;
         if (mEyeRoration > PI2)
-            mEyeRoration = PI2;
+            mEyeRoration -= PI2;
         else if (mEyeRoration < 0)
-            mEyeRoration = 0;
+            mEyeRoration += PI2;
     }
 
     void MillSimulation::MoveEye(float x, float z)
@@ -480,7 +480,7 @@ namespace MillSim {
     {
         // gray background
         glClearColor(0.6f, 0.8f, 1.0f, 1.0f);
-
+        mEyeRoration = 0.0;
 
         // use shaders
         //   standard diffuse shader
diff --git a/src/Mod/CAM/PathSimulator/AppGL/OpenGlWrapper.h b/src/Mod/CAM/PathSimulator/AppGL/OpenGlWrapper.h
index 11c144fb6b..92ad6483de 100644
--- a/src/Mod/CAM/PathSimulator/AppGL/OpenGlWrapper.h
+++ b/src/Mod/CAM/PathSimulator/AppGL/OpenGlWrapper.h
@@ -28,6 +28,9 @@
 #include "DlgCAMSimulator.h"
 extern QOpenGLContext* gOpenGlContext;
 #define gSimWindow CAMSimulator::DlgCAMSimulator::GetInstance()
+#define glClearColor gSimWindow->glClearColor
+#define glBlendFunc gSimWindow->glBlendFunc
+#define glClear gSimWindow->glClear
 #define glGenBuffers gSimWindow->glGenBuffers
 #define glBindBuffer gSimWindow->glBindBuffer
 #define glBufferData gSimWindow->glBufferData