pillar + check Mmatrix again

DiffractionGratings/grating3D.geo

@@ -213,6 +213,11 @@
     Box(9) = {-period_x/2,-ry/2, hh_L_3, period_x, ry, rz};
   EndIf
   
+  If (tag_geom==8)
+    Cylinder(9) = {0,0,hh_L_3 , 0,0,rz , rx};
+    Dilate { { 0,0,hh_L_3 }, { 1, ry/rx, 1 } } { Volume{9}; }
+  EndIf
+  
   
   Coherence;
   Call SetPBCs;