I don't know the specifics of exporting from 3D Studio Max but my understanding has been that separate materials=separate surfaces, and conversely same material=same surface.
At least within a single object. Sswift's point about separate objects is important, that the separate objects/entities thing would still matter. Because even if all the objects have the same material, separate objects are always separate surfaces. In most of the levels I've seen created in 3D Studio Max, people went crazy with separate objects and/or were lazy about combining objects, resulting in a separate object (and thus separate surface) for every little detail in the scene.
At least within a single object. Sswift's point about separate objects is important, that the separate objects/entities thing would still matter. Because even if all the objects have the same material, separate objects are always separate surfaces. In most of the levels I've seen created in 3D Studio Max, people went crazy with separate objects and/or were lazy about combining objects, resulting in a separate object (and thus separate surface) for every little detail in the scene.