diff --git a/gen/SkinPartition.cpp b/gen/SkinPartition.cpp
index c9828b05e024f17baa319a3b29568a9c48c154fb..56c6136db907597fd4e94d1af03b2bc2128b8ae5 100644
--- a/gen/SkinPartition.cpp
+++ b/gen/SkinPartition.cpp
@@ -17,8 +17,7 @@ ushort SkinPartition::CalcNumTriangles() const {
       size = (ushort)triangles.size();
    } else {
       for (size_t i=0; i<stripLengths.size(); ++i)
-         size += (ushort)stripLengths[i];
-      size -= 2;
+         size += ((ushort)stripLengths[i] - 2);
    }
    return size;
 }
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