diff --git a/source/blender/blenkernel/intern/DerivedMesh.c b/source/blender/blenkernel/intern/DerivedMesh.c
index aaddc2dfcc5..dc54fc7c1f0 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.c
+++ b/source/blender/blenkernel/intern/DerivedMesh.c
@@ -983,7 +983,7 @@ static DerivedMesh *getEditMeshDerivedMesh(EditMesh *em, Object *ob,
 			float *no = emdm->faceNos[i];
 			
 			if(efa->v4) {
-				float *v4 = vertexCos[(int) efa->v3->tmp.l];
+				float *v4 = vertexCos[(int) efa->v4->tmp.l];
 
 				CalcNormFloat4(v1, v2, v3, v4, no);
 				VecAddf(emdm->vertexNos[(int) efa->v4->tmp.l], emdm->vertexNos[(int) efa->v4->tmp.l], no);