From f4ea1eb341b99ec95a3d17b1d8a65d413d957f19 Mon Sep 17 00:00:00 2001
From: andy <andy>
Date: Thu, 8 Sep 2011 16:01:17 +0100
Subject: [PATCH] ENH: Added mag(normal) check to AMI face area intersect calc
 for robustness

---
 .../AMIInterpolation/AMIInterpolation/AMIInterpolation.C    | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolation.C b/src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolation.C
index 96248f48a6..493d3eaaa8 100644
--- a/src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolation.C
+++ b/src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolation.C
@@ -781,7 +781,11 @@ Foam::scalar Foam::AMIInterpolation<SourcePatch, TargetPatch>::interArea
     // crude resultant norm
     const vector n = 0.5*(tgt.normal(tgtPoints) - src.normal(srcPoints));
 
-    scalar area = inter.calc(src, tgt, n, triMode_);
+    scalar area = 0;
+    if (mag(n) > ROOTVSMALL)
+    {
+        area = inter.calc(src, tgt, n, triMode_);
+    }
 
     if ((debug > 1) && (area > 0))
     {