Fix dirty shadows on mesh models

models/moreblocks_slope_inner_cut_half.obj

@@ -1,22 +1,34 @@
-v 0.500000 0.000000 0.500000
-v -0.500000 0.000000 0.500000
+# Blender v2.72 (sub 0) OBJ File: ''
+# www.blender.org
+mtllib moreblocks_slope_inner_cut_half.mtl
+o moreblocks_slope_inner_cut_half
 v 0.500000 -0.500000 0.500000
-v -0.500000 -0.500000 0.500000
-v 0.500000 0.000000 -0.500000
 v 0.500000 -0.500000 -0.500000
+v 0.500000 0.000000 -0.500000
+v 0.500000 -0.000000 0.500000
+v -0.500000 -0.500000 0.500000
+v -0.500000 -0.000000 0.500000
 v -0.500000 -0.500000 -0.500000
 vt 0.000000 0.000000
-vt 0.500000 0.000000
 vt 1.000000 0.000000
-vt 0.000000 0.500000
 vt 1.000000 0.500000
-vt 0.000000 1.000000
+vt 0.000000 0.500000
 vt 1.000000 1.000000
+vt 0.000000 1.000000
+vt 0.500000 0.000000
+vn 1.000000 0.000000 0.000000
+vn 0.000000 -0.000000 1.000000
+vn 0.000000 -1.000000 -0.000000
+vn 0.000000 1.000000 0.000000
+vn -1.000000 0.000000 0.000000
+vn 0.000000 0.000000 -1.000000
+vn -0.408200 0.816500 -0.408200
+usemtl None
 s off
-f 3/1 6/3 5/5 1/4
-f 4/1 3/3 1/5 2/4
-f 6/1 3/3 4/7 7/6
-f 2/1 1/3 5/7
-f 7/1 4/3 2/5
-f 6/1 7/3 5/4
-f 7/2 2/7 5/6
+f 1/1/1 2/2/1 3/3/1 4/4/1
+f 5/1/2 1/2/2 4/3/2 6/4/2
+f 2/1/3 1/2/3 5/5/3 7/6/3
+f 6/1/4 4/2/4 3/5/4
+f 7/1/5 5/2/5 6/3/5
+f 2/1/6 7/2/6 3/4/6
+f 7/7/7 6/5/7 3/6/7