[Closed] rebuild Mesh's normals [SDK]

Hi,
I have the following problem: I have an object of type “Mesh” and I want to get vertex normal. I was wondering why I can’t get normal with obj->getNormal() but I realized that first I need to execute obj->buildNormals(). Okay, but then I move some vertices, the normals don’t update and the obj->buildNormals() executed for the second time gives no results, it works only for meshes without normals. My question is how to update those normals? I know about MNMesh class, but it has to work with Mesh (or triObject) class.