The number of mesh vertices increases when the object is imported unity from Max

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the number of mesh vertices increases when the object is imported unity from Max.
For example the cube in the picture.However,the cube should only has 8 vertices.Someone could help me or give me some reason?Tanks a lot!!!
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3DS max allows you to ‘weld’ vertices, which is just shorthand for pairing up vertices so all values are equal and a change to one will change the other - welding does not reduce the actual vertex count, which is what Unity uses. In your Max model, the corners are welded; in Unity welds are meaningless, since when you send a mesh to the GPU for rendering you need a different normal for each of the 3 vertices in each corner (corresponding to the 3 faces that end at that point). So your total vert count would be 6 sides * 4 corners / side = 24 verts.

In Unity you can reuse vertices in multiple triangles, so you could create an 8-vertex cube, but that would mean that the cube would have no hard edges - it would be rendered as if all edges were rounded. This is because you would have to combine the 3 normals and tangents at each corner into 1 shared normal and tangent.

Very very good and short explanation +1 edit Even this question has already been asked i've upvoted the question as well, just bacause of the answer ;) <a href="http://answers.unity3d.com/questions/21411/vertices-and-triangle-in-unity-problem-with-counti.html">1</a> <a href="http://forum.unity3d.com/threads/50576-Unity-multiplying-my-poly-count">2</a> <a href="http://answers.unity3d.com/questions/37435/why-is-unity-got-more-vertices-than-3dsmax.html">3</a>

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Not really a new answer, but a bit of an addition: Meshes are always split at Smoothing Groups, Material borders and UV borders, when they are imported in a realtime environment, since one XYZ Vertex can ever only have one UV coordinate, one vertex normal and one material.

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