normalized Z axis is always positive

Hi all. I have a question about normalize coordinates that you get from the mesh. I'm trying to do a simple Sphere, but for some reason I create only one half and the other not. I have observed that this is due to the fact that the coordinates "vertices[i].z" is always positive and never negative. I would like to ask if you do not know what is wrong. Thank you :) Mesh mesh = GetComponent().mesh; Vector3[] vertices = mesh.vertices; Vector3[] verticesN = vertices; int k = 0; for (var i = 0; i = 100) { Instantiate(sp_debug, verticesN[i], Quaternion.identity); k = 0; } k++; } mesh.vertices = verticesN; mesh.RecalculateNormals(); (Red sphere on picture are only for my debug. You can see there are only half sphere) ![alt text][1] [1]: /storage/temp/30672-sphere.png