You dont have to model in tris, model in quads, its easier then triagulate the mesh, though it does not matter if there is the odd tri in there (same as normal modeling).

Tris are needed as this is the default for a games engine, it does not need to tesalate the geo when running.

When you render a quad mesh in maya it converts it into tris as part of the rendering process, you just dont see it do it.