diff --git a/Cassiopee/Connector/Connector/IBM.py b/Cassiopee/Connector/Connector/IBM.py
index d50b1c24a..c4ffe0a13 100644
--- a/Cassiopee/Connector/Connector/IBM.py
+++ b/Cassiopee/Connector/Connector/IBM.py
@@ -192,15 +192,26 @@ def prepareIBMData(t_case, t_out, tc_out, t_in=None, to=None, tbox=None, tinit=N
 
     if isinstance(t_case, str): tb = C.convertFile2PyTree(t_case)
     else: tb = Internal.copyTree(t_case)
-
-    ##THIS IS TEMPORARY -> a more comprehensive test is in the works and will make this
-    ## print redundant.
-    if cartesian and t_in:
-        RED  = "\033[1;31;40m"
-        END  = "\033[0m"
-        print(RED + "===========================================" + END)
-        print("Note: Assuming " + RED + "CARTESIAN " + END + "grid")
-        print(RED + "===========================================" + END)
+    
+    ## Note: cartesian = True is left as an input argument to avoid regressing  during the non-regression test.
+    ##       In the near future the ref. values for the non-regression tests will be updated with cartesian=True.
+    ##       At this point, cartesian=True input argument can be deleted.
+    ## Note: when cartesian = True is deleted as an input argument the line below must be uncommented and the cartesian in the if statement but be deleted.
+    #cartesian = True
+    if t_in and cartesian:
+        cartesian = G_IBM.checkCartesian(t_in, nghost=2)
+        if cartesian:
+            RED  = "\033[1;31;40m"
+            END  = "\033[0m"
+            print("===========================================")
+            print("Note: t_in is a " + RED + "CARTESIAN " + END + "grid")
+            print("===========================================")
+        else:
+            RED  = "\033[1;31;40m"
+            END  = "\033[0m"
+            print("===========================================")
+            print("Note: t_in is " + RED + "NOT" + END + " a " + RED + "CARTESIAN " + END + "grid")
+            print("===========================================")
     
     ##[AJ] keep for now...will delete in the near future
     ##if isinstance(tc_out, str):
diff --git a/Cassiopee/Generator/Generator/IBM.py b/Cassiopee/Generator/Generator/IBM.py
index 3e9bfbcd9..0925eb5c0 100644
--- a/Cassiopee/Generator/Generator/IBM.py
+++ b/Cassiopee/Generator/Generator/IBM.py
@@ -1309,3 +1309,50 @@ def extrudeCartesianZDir(t, tb, check=False, extrusion="cart", dz=0.01, NPas=10,
     X_IBM._redispatch__(t=t)                    
     return t, tb
 
+
+def checkCartesian(t, nghost=0):
+    dimPb = Internal.getNodeFromName(t, 'EquationDimension')
+    if dimPb is None: raise ValueError('prepareIBMData: EquationDimension is missing in input tree.')
+    dimPb = Internal.getValue(dimPb)
+
+    nghostZ=0
+    if dimPb==3: nghostZ=nghost
+
+    isCartesian=1
+    for z in Internal.getZones(t):
+        ##X Direction
+        coord = Internal.getNodeFromName(z,'CoordinateX')[1]
+        i     = 0
+        dx    = coord[i+1+nghost, 0+nghost, 0+nghostZ] - coord[i  +nghost, 0+nghost, 0+nghostZ]
+        for i in range(1,4):
+            dx2  = coord[i+1+nghost, 0+nghost, 0+nghostZ] - coord[i  +nghost, 0+nghost, 0+nghostZ]
+            diff = abs(dx2-dx)
+            if diff>1e-12: isCartesian=0
+        if isCartesian<1:break
+
+        ##Y Direction
+        coord = Internal.getNodeFromName(z,'CoordinateY')[1]
+        i     = 0
+        dx    = coord[0+nghost,i+1+nghost,0+nghostZ] - coord[0+nghost,i  +nghost,0+nghostZ]
+        for i in range(1,4):
+            dx2  = coord[0+nghost,i+1+nghost,0+nghostZ] - coord[0+nghost,i  +nghost,0+nghostZ]
+            diff = abs(dx2-dx)
+            if diff>1e-12: isCartesian=0
+        if isCartesian<1:break
+
+
+        ##Z Direction
+        if dimPb==3:
+            coord = Internal.getNodeFromName(z,'CoordinateZ')[1]
+            i     = 0
+            dx    = coord[0+nghost,0+nghost,i+1+nghost] - coord[0+nghost,0+nghost,i  +nghost]
+            for i in range(1,4):
+                dx2  = coord[0+nghost,0+nghost,i+1+nghost] - coord[0+nghost,0+nghost,i  +nghost]
+                diff = abs(dx2-dx)
+                if diff>1e-12: isCartesian=0
+        if isCartesian<1:break
+
+    isCartesian=Cmpi.allreduce(isCartesian,op=Cmpi.MIN)
+    if isCartesian==1:cartesian=True
+    else:             cartesian=False
+    return cartesian
diff --git a/Cassiopee/Generator/test/checkCartesian_m1.py b/Cassiopee/Generator/test/checkCartesian_m1.py
new file mode 100644
index 000000000..bb718a11c
--- /dev/null
+++ b/Cassiopee/Generator/test/checkCartesian_m1.py
@@ -0,0 +1,79 @@
+# - check if mesh is cartesian -
+import Transform.PyTree as T
+import KCore.test as test
+import Converter.PyTree as C
+import Converter.Internal as Internal
+import Generator.PyTree as G
+import Generator.IBM as G_IBM
+import Distributor2.PyTree as D2
+import Converter.Mpi as Cmpi
+import random
+
+if Cmpi.rank==0:
+    a = G.cart((0.,0.,0.), (0.1,0.1,1), (40,40,40))
+    t = C.newPyTree(['CARTESIAN', a])
+    C._addState(t, 'EquationDimension', 3)
+    
+    t       = T.splitNParts(t, 10)
+    t,stats = D2.distribute(t, 2)
+    C.convertPyTree2File(t,'t_TMP.cgns')
+t=Cmpi.convertFile2PyTree('t_TMP.cgns',proc=Cmpi.rank)
+
+##Test 1 - Cartesian
+cartesian=G_IBM.checkCartesian(t)
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+if Cmpi.rank==0:
+    test.testT(t,1)
+    print('Is Cartesian::',cartesian,isCartesian)
+tsave = Internal.copyTree(t)
+#C.convertPyTree2File(t,'t_test1.cgns')
+
+## Test 2 - Z direction is non homogenous --> non Cartesian mesh
+Internal._rmNode(t, Internal.getNodeFromName(t, 'TMP_Node'))
+coord = Internal.getNodeFromName(Internal.getZones(t)[0],'CoordinateZ')[1]
+for i in range(6): coord[:,:,i]=coord[:,:,i]*i/10+coord[:,:,i]
+cartesian=G_IBM.checkCartesian(t)
+
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+if Cmpi.rank==0:
+    test.testT(t,2)
+    print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test2.cgns')
+
+## Test 3 - Y direction is non homogenous --> non Cartesian mesh
+t = Internal.copyTree(tsave)
+Internal._rmNode(t, Internal.getNodeFromName(t, 'TMP_Node'))
+coord = Internal.getNodeFromName(Internal.getZones(t)[0],'CoordinateY')[1]
+for i in range(6): coord[:,i,:]=coord[:,i,:]*i/10+coord[:,i,:]
+cartesian=G_IBM.checkCartesian(t)
+
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+if Cmpi.rank==0:
+    test.testT(t,3)
+    print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test3.cgns')
+
+## Test 4 - Z direction is non homogenous --> non Cartesian mesh
+t = Internal.copyTree(tsave)
+Internal._rmNode(t, Internal.getNodeFromName(t, 'TMP_Node'))
+coord = Internal.getNodeFromName(Internal.getZones(t)[0],'CoordinateX')[1]
+for i in range(6): coord[i,:,:]=coord[i,:,:]*i/10+coord[i,:,:]
+cartesian=G_IBM.checkCartesian(t)
+
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+if Cmpi.rank==0:
+    test.testT(t,4)
+    print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test4.cgns')
diff --git a/Cassiopee/Generator/test/checkCartesian_t1.py b/Cassiopee/Generator/test/checkCartesian_t1.py
new file mode 100644
index 000000000..5eeee69ca
--- /dev/null
+++ b/Cassiopee/Generator/test/checkCartesian_t1.py
@@ -0,0 +1,67 @@
+# - check if mesh is cartesian -
+import Transform.PyTree as T
+import KCore.test as test
+import Converter.PyTree as C
+import Converter.Internal as Internal
+import Generator.PyTree as G
+import Generator.IBM as G_IBM
+import random
+
+a = G.cart((0.,0.,0.), (0.1,0.1,1), (20,20,20))
+t = C.newPyTree(['CARTESIAN', a])
+C._addState(t, 'EquationDimension', 3)
+
+##Test 1 - Cartesian
+cartesian=G_IBM.checkCartesian(t)
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+test.testT(t,1)
+tsave = Internal.copyTree(t)
+print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test1.cgns')
+
+## Test 2 - Z direction is non homogenous --> non Cartesian mesh
+Internal._rmNode(t, Internal.getNodeFromName(t, 'TMP_Node'))
+coord = Internal.getNodeFromName(t,'CoordinateZ')[1]
+for i in range(6): coord[:,:,i]=coord[:,:,i]*i/10+coord[:,:,i]
+cartesian=G_IBM.checkCartesian(t)
+
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+test.testT(t,2)
+print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test2.cgns')
+
+## Test 3 - Y direction is non homogenous --> non Cartesian mesh
+t = Internal.copyTree(tsave)
+Internal._rmNode(t, Internal.getNodeFromName(t, 'TMP_Node'))
+coord = Internal.getNodeFromName(t,'CoordinateY')[1]
+for i in range(6): coord[:,i,:]=coord[:,i,:]*i/10+coord[:,i,:]
+cartesian=G_IBM.checkCartesian(t)
+
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+test.testT(t,3)
+print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test3.cgns')
+
+## Test 4 - Z direction is non homogenous --> non Cartesian mesh
+t = Internal.copyTree(tsave)
+Internal._rmNode(t, Internal.getNodeFromName(t, 'TMP_Node'))
+coord = Internal.getNodeFromName(t,'CoordinateX')[1]
+for i in range(6): coord[i,:,:]=coord[i,:,:]*i/10+coord[i,:,:]
+cartesian=G_IBM.checkCartesian(t)
+
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+test.testT(t,4)
+print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test4.cgns')
diff --git a/Cassiopee/Generator/test/checkCartesian_t2.py b/Cassiopee/Generator/test/checkCartesian_t2.py
new file mode 100644
index 000000000..689fa1698
--- /dev/null
+++ b/Cassiopee/Generator/test/checkCartesian_t2.py
@@ -0,0 +1,53 @@
+# - check if mesh is cartesian -
+import Transform.PyTree as T
+import KCore.test as test
+import Converter.PyTree as C
+import Converter.Internal as Internal
+import Generator.PyTree as G
+import Generator.IBM as G_IBM
+import random
+
+a = G.cart((0.,0.,0.), (0.1,0.1,1), (20,20,2))
+t = C.newPyTree(['CARTESIAN', a])
+C._addState(t, 'EquationDimension', 2)
+
+##Test 1 - Cartesian
+cartesian=G_IBM.checkCartesian(t)
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+test.testT(t,1)
+tsave = Internal.copyTree(t)
+print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test1.cgns')
+
+## Test 2 - Y direction is non homogenous --> non Cartesian mesh
+t = Internal.copyTree(tsave)
+Internal._rmNode(t, Internal.getNodeFromName(t, 'TMP_Node'))
+coord = Internal.getNodeFromName(t,'CoordinateY')[1]
+for i in range(6): coord[:,i,:]=coord[:,i,:]*i/10+coord[:,i,:]
+cartesian=G_IBM.checkCartesian(t)
+
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+test.testT(t,2)
+print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test2.cgns')
+
+## Test 3 - Z direction is non homogenous --> non Cartesian mesh
+t = Internal.copyTree(tsave)
+Internal._rmNode(t, Internal.getNodeFromName(t, 'TMP_Node'))
+coord = Internal.getNodeFromName(t,'CoordinateX')[1]
+for i in range(6): coord[i,:,:]=coord[i,:,:]*i/10+coord[i,:,:]
+cartesian=G_IBM.checkCartesian(t)
+
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+test.testT(t,3)
+print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test3.cgns')
diff --git a/Cassiopee/Generator/test/checkCartesian_t3.py b/Cassiopee/Generator/test/checkCartesian_t3.py
new file mode 100644
index 000000000..9f40dbb3a
--- /dev/null
+++ b/Cassiopee/Generator/test/checkCartesian_t3.py
@@ -0,0 +1,69 @@
+# - check if mesh is cartesian -
+import Transform.PyTree as T
+import KCore.test as test
+import Converter.PyTree as C
+import Converter.Internal as Internal
+import Generator.PyTree as G
+import Generator.IBM as G_IBM
+import random
+
+a = G.cart((0.,0.,0.), (0.1,0.1,1), (40,40,40))
+t = C.newPyTree(['CARTESIAN', a])
+C._addState(t, 'EquationDimension', 3)
+    
+t = T.splitNParts(t, 10)
+
+##Test 1 - Cartesian
+cartesian=G_IBM.checkCartesian(t)
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+test.testT(t,1)
+tsave = Internal.copyTree(t)
+print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test1.cgns')
+
+## Test 2 - Z direction is non homogenous --> non Cartesian mesh
+Internal._rmNode(t, Internal.getNodeFromName(t, 'TMP_Node'))
+coord = Internal.getNodeFromName(Internal.getZones(t)[0],'CoordinateZ')[1]
+for i in range(6): coord[:,:,i]=coord[:,:,i]*i/10+coord[:,:,i]
+cartesian=G_IBM.checkCartesian(t)
+
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+test.testT(t,2)
+print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test2.cgns')
+
+## Test 3 - Y direction is non homogenous --> non Cartesian mesh
+t = Internal.copyTree(tsave)
+Internal._rmNode(t, Internal.getNodeFromName(t, 'TMP_Node'))
+coord = Internal.getNodeFromName(Internal.getZones(t)[0],'CoordinateY')[1]
+for i in range(6): coord[:,i,:]=coord[:,i,:]*i/10+coord[:,i,:]
+cartesian=G_IBM.checkCartesian(t)
+
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+test.testT(t,3)
+print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test3.cgns')
+
+## Test 4 - Z direction is non homogenous --> non Cartesian mesh
+t = Internal.copyTree(tsave)
+Internal._rmNode(t, Internal.getNodeFromName(t, 'TMP_Node'))
+coord = Internal.getNodeFromName(Internal.getZones(t)[0],'CoordinateX')[1]
+for i in range(6): coord[i,:,:]=coord[i,:,:]*i/10+coord[i,:,:]
+cartesian=G_IBM.checkCartesian(t)
+
+isCartesian=0
+if cartesian:isCartesian=1
+Internal._createUniqueChild(t, 'TMP_Node', 'UserDefinedData_t')
+Internal._createUniqueChild(Internal.getNodeFromName1(t, 'TMP_Node'), 'Cartesian', 'DataArray_t', value=isCartesian)
+test.testT(t,4)
+print('Is Cartesian::',cartesian,isCartesian)
+#C.convertPyTree2File(t,'t_test4.cgns')