diff --git a/src/meshTools/AMIInterpolation/patches/cyclicAMI/cyclicAMIPolyPatch/cyclicAMIPolyPatch.C b/src/meshTools/AMIInterpolation/patches/cyclicAMI/cyclicAMIPolyPatch/cyclicAMIPolyPatch.C
index cb92236994df1c182eff83d2942b8978eddca8ef..f58e99ce0e01e65646c8275b51513334e48eaef0 100644
--- a/src/meshTools/AMIInterpolation/patches/cyclicAMI/cyclicAMIPolyPatch/cyclicAMIPolyPatch.C
+++ b/src/meshTools/AMIInterpolation/patches/cyclicAMI/cyclicAMIPolyPatch/cyclicAMIPolyPatch.C
@@ -261,7 +261,7 @@ void Foam::cyclicAMIPolyPatch::calcTransforms
 
                 if (debug)
                 {
-                    scalar theta = radToDeg(acos(n0 & n1));
+                    scalar theta = radToDeg(acos(-(n0 & n1)));
 
                     Pout<< "cyclicAMIPolyPatch::calcTransforms: patch:"
                         << name()