If you are keeping the mesh in Maya and aren't modifying it after the fact, you don't need to triangulate. Keep in mind your quad mesh is actually still made up of triangles, the lines joining them are simply hidden and usually re-evaluated whenever you move a vertex, which is the reason behind triangulating them before…
Little update--- when I chose Object space instead Tangent space everything almost ok. (in Maya's viewport--high quality and viewport 2.0) I can manually move vertex normal that make problematic edges good but this method make distortion on another nearest edges.
No-no... I use owerall Soften for all model. Hard edges will look more terrible if no splits in UVs. It's look like (not 100%) this problem from http://polycount.com/discussion/107196/youre-making-me-hard-making-sense-of-hard-edges-uvs-normal-maps-and-vertex-counts/p1 But in my case not all edges visible. And I tried ABC…