diff --git a/Circular_kernel_3/demo/Circular_kernel_3/Viewer.cpp b/Circular_kernel_3/demo/Circular_kernel_3/Viewer.cpp
index 683ef342a62..6eeff6fd3e0 100644
--- a/Circular_kernel_3/demo/Circular_kernel_3/Viewer.cpp
+++ b/Circular_kernel_3/demo/Circular_kernel_3/Viewer.cpp
@@ -316,8 +316,8 @@ void Viewer::compute_elements()
 
 
 
-            P = rings*M_PI/180.0;
-            T = t*M_PI/180.0;
+            P = rings*CGAL_PI/180.0;
+            T = t*CGAL_PI/180.0;
             x[1] = sin(P) * cos(T) ;
             y[1] = sin(P) * sin(T) ;
             z[1] = cos(P);
@@ -331,8 +331,8 @@ void Viewer::compute_elements()
             normals.push_back(z[1]);
 
             //
-            P = rings*M_PI/180.0;
-            T = (t+sectors)*M_PI/180.0;
+            P = rings*CGAL_PI/180.0;
+            T = (t+sectors)*CGAL_PI/180.0;
             x[2] = sin(P) * cos(T) ;
             y[2] = sin(P) * sin(T) ;
             z[2] = cos(P);
@@ -351,8 +351,8 @@ void Viewer::compute_elements()
             for(int t=0; t<360; t+=sectors)
             {
                 //A
-                P = p*M_PI/180.0;
-                T = t*M_PI/180.0;
+                P = p*CGAL_PI/180.0;
+                T = t*CGAL_PI/180.0;
                 x[0] = sin(P) * cos(T) ;
                 y[0] = sin(P) * sin(T) ;
                 z[0] = cos(P);
@@ -367,8 +367,8 @@ void Viewer::compute_elements()
                 normals.push_back(z[0]);
 
                 //B
-                P = (p+rings)*M_PI/180.0;
-                T = t*M_PI/180.0;
+                P = (p+rings)*CGAL_PI/180.0;
+                T = t*CGAL_PI/180.0;
                 x[1] = sin(P) * cos(T) ;
                 y[1] = sin(P) * sin(T) ;
                 z[1] = cos(P);
@@ -382,8 +382,8 @@ void Viewer::compute_elements()
                 normals.push_back(z[1]);
 
                 //C
-                P = p*M_PI/180.0;
-                T = (t+sectors)*M_PI/180.0;
+                P = p*CGAL_PI/180.0;
+                T = (t+sectors)*CGAL_PI/180.0;
                 x[2] = sin(P) * cos(T) ;
                 y[2] = sin(P) * sin(T) ;
                 z[2] = cos(P);
@@ -396,8 +396,8 @@ void Viewer::compute_elements()
                 normals.push_back(y[2]);
                 normals.push_back(z[2]);
                 //D
-                P = (p+rings)*M_PI/180.0;
-                T = (t+sectors)*M_PI/180.0;
+                P = (p+rings)*CGAL_PI/180.0;
+                T = (t+sectors)*CGAL_PI/180.0;
                 x[3] = sin(P) * cos(T) ;
                 y[3] = sin(P) * sin(T) ;
                 z[3] = cos(P);
@@ -446,8 +446,8 @@ void Viewer::compute_elements()
             normals.push_back(-1);
 
 
-            P = (180-rings)*M_PI/180.0;
-            T = t*M_PI/180.0;
+            P = (180-rings)*CGAL_PI/180.0;
+            T = t*CGAL_PI/180.0;
             x[1] = sin(P) * cos(T) ;
             y[1] = sin(P) * sin(T) ;
             z[1] = cos(P);
@@ -461,8 +461,8 @@ void Viewer::compute_elements()
             normals.push_back(z[1]);
 
 
-            P = (180-rings)*M_PI/180.0;
-            T = (t+sectors)*M_PI/180.0;
+            P = (180-rings)*CGAL_PI/180.0;
+            T = (t+sectors)*CGAL_PI/180.0;
             x[2] = sin(P) * cos(T) ;
             y[2] = sin(P) * sin(T) ;
             z[2] = cos(P);
@@ -501,8 +501,8 @@ void Viewer::compute_elements()
 
 
 
-            P = rings*M_PI/180.0;
-            T = t*M_PI/180.0;
+            P = rings*CGAL_PI/180.0;
+            T = t*CGAL_PI/180.0;
             x[1] = sin(P) * cos(T) ;
             y[1] = sin(P) * sin(T) ;
             z[1] = cos(P);
@@ -516,8 +516,8 @@ void Viewer::compute_elements()
             normals_inter.push_back(z[1]);
 
             //
-            P = rings*M_PI/180.0;
-            T = (t+sectors)*M_PI/180.0;
+            P = rings*CGAL_PI/180.0;
+            T = (t+sectors)*CGAL_PI/180.0;
             x[2] = sin(P) * cos(T) ;
             y[2] = sin(P) * sin(T) ;
             z[2] = cos(P);
@@ -536,8 +536,8 @@ void Viewer::compute_elements()
             for(int t=0; t<360; t+=sectors)
             {
                 //A
-                P = p*M_PI/180.0;
-                T = t*M_PI/180.0;
+                P = p*CGAL_PI/180.0;
+                T = t*CGAL_PI/180.0;
                 x[0] = sin(P) * cos(T) ;
                 y[0] = sin(P) * sin(T) ;
                 z[0] = cos(P);
@@ -552,8 +552,8 @@ void Viewer::compute_elements()
                 normals_inter.push_back(z[0]);
 
                 //B
-                P = (p+rings)*M_PI/180.0;
-                T = t*M_PI/180.0;
+                P = (p+rings)*CGAL_PI/180.0;
+                T = t*CGAL_PI/180.0;
                 x[1] = sin(P) * cos(T) ;
                 y[1] = sin(P) * sin(T) ;
                 z[1] = cos(P);
@@ -567,8 +567,8 @@ void Viewer::compute_elements()
                 normals_inter.push_back(z[1]);
 
                 //C
-                P = p*M_PI/180.0;
-                T = (t+sectors)*M_PI/180.0;
+                P = p*CGAL_PI/180.0;
+                T = (t+sectors)*CGAL_PI/180.0;
                 x[2] = sin(P) * cos(T) ;
                 y[2] = sin(P) * sin(T) ;
                 z[2] = cos(P);
@@ -581,8 +581,8 @@ void Viewer::compute_elements()
                 normals_inter.push_back(y[2]);
                 normals_inter.push_back(z[2]);
                 //D
-                P = (p+rings)*M_PI/180.0;
-                T = (t+sectors)*M_PI/180.0;
+                P = (p+rings)*CGAL_PI/180.0;
+                T = (t+sectors)*CGAL_PI/180.0;
                 x[3] = sin(P) * cos(T) ;
                 y[3] = sin(P) * sin(T) ;
                 z[3] = cos(P);
@@ -631,8 +631,8 @@ void Viewer::compute_elements()
             normals_inter.push_back(-1);
 
 
-            P = (180-rings)*M_PI/180.0;
-            T = t*M_PI/180.0;
+            P = (180-rings)*CGAL_PI/180.0;
+            T = t*CGAL_PI/180.0;
             x[1] = sin(P) * cos(T) ;
             y[1] = sin(P) * sin(T) ;
             z[1] = cos(P);
@@ -646,8 +646,8 @@ void Viewer::compute_elements()
             normals_inter.push_back(z[1]);
 
 
-            P = (180-rings)*M_PI/180.0;
-            T = (t+sectors)*M_PI/180.0;
+            P = (180-rings)*CGAL_PI/180.0;
+            T = (t+sectors)*CGAL_PI/180.0;
             x[2] = sin(P) * cos(T) ;
             y[2] = sin(P) * sin(T) ;
             z[2] = cos(P);