diff --git a/src/Mod/TechDraw/Gui/QGIViewDimension.cpp b/src/Mod/TechDraw/Gui/QGIViewDimension.cpp
index c76030adc704..1c5c1a6db418 100644
--- a/src/Mod/TechDraw/Gui/QGIViewDimension.cpp
+++ b/src/Mod/TechDraw/Gui/QGIViewDimension.cpp
@@ -21,6 +21,12 @@
  ***************************************************************************/
 
 #include "PreCompiled.h"
+
+#ifdef FC_OS_WIN32
+#define _USE_MATH_DEFINES            //re Windows & M_PI issues
+#endif
+#include <cmath>
+
 #ifndef _PreComp_
   #include <BRep_Builder.hxx>
   #include <TopoDS_Compound.hxx>
@@ -36,7 +42,6 @@
   # include <QPaintDevice>
   # include <QSvgGenerator>
 
-  # include <cmath>
 #endif
 
 #include <App/Application.h>
@@ -2271,4 +2276,20 @@ void QGIViewDimension::setPens(void)
     aHead2->setWidth(m_lineWidth);
 }
 
+double QGIViewDimension::toDeg(double a) 
+{
+    return a*180/M_PI;
+}
+
+double QGIViewDimension::toQtRad(double a) 
+{
+    return -a; 
+}
+
+double QGIViewDimension::toQtDeg(double a) 
+{
+    return -a*180.0/M_PI; 
+}
+
+
 #include <Mod/TechDraw/Gui/moc_QGIViewDimension.cpp>
diff --git a/src/Mod/TechDraw/Gui/QGIViewDimension.h b/src/Mod/TechDraw/Gui/QGIViewDimension.h
index a9ea1ef6f617..86df34cc6017 100644
--- a/src/Mod/TechDraw/Gui/QGIViewDimension.h
+++ b/src/Mod/TechDraw/Gui/QGIViewDimension.h
@@ -271,9 +271,9 @@ public Q_SLOTS:
                              { return QRectF(Rez::guiX(r.MinX), -Rez::guiX(r.MaxY),
                                              Rez::guiX(r.Width()), Rez::guiX(r.Height())); }
 
-    static inline double toDeg(double a) { return a*180/M_PI; }
-    static inline double toQtRad(double a) { return -a; }
-    static inline double toQtDeg(double a) { return -a*180.0/M_PI; }
+    static double toDeg(double a);
+    static double toQtRad(double a);
+    static double toQtDeg(double a);
 
     double getDefaultExtensionLineOverhang() const;
     double getDefaultArrowTailLength() const;