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diff --git a/apps/metro/sample/readme.txt b/apps/metro/sample/readme.txt
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+This directory contains four 3d models that can be used to test metro. The models represent the same toroidal knot at two different level of details.
+
+- knot_orig.ply           12800 vertexes, 25600 triangles: the original high resolution mesh
+- knot_subsampled.ply       800 vertexes,  1600 triangles: a low res model obtained by simple uniform subsampling
+- knot_vcg_simplified.ply   800 vertexes,  1600 triangles: a low res model obtained by our library simplification code
+- knot_max_simplified.stl   800 vertexes,  1600 triangles: a low res model obtained by using a commercial tool
+