Hi.. Found this interesting post here and i want to contribute because i use Rhino on my daily work and 3ds max at home.
Well! There was the MoI 3D in which you can add ngons on exports but today we have Rhinoceros 7 and their retopology + sub-D methods.
Although i have been struggling with this to.
What i found:
Simple geometries like regular extrudes, boxes, surfaces... All kind of regular solid its better to export as simple DWG.
All geometry goes clean and retain layers information. Perfect here.
Complex geometries, like curves, parabolas, hyperbolic, or any other curved surface object, let say, a wash basin, a tap water, a toilet, a car, or any similar, there is a need on this objects to be clean as possible. Mostly close and well modeled. After you can retopology them before export.
From here i found .STEP a good non kill curves. No faces triangulates. All viewport seems clean. But then when you need to convert to poly for Chamfer purposes or any other, we get Fuc...ked.
OBJ, FBX, 3DS max formats, some how is a mess but they retain all information in export.
If the geometry is a mesh you can select all edges and press "clean edges" in the modifier panel. The weld vertex.
Conclusions... Still today i never found a good explanation for this. As far i have found it is because of the NURBS Algorithm from Rhino department.
Its a pain to get rid of those tessellations in viewport.
If there is anyone with a googd solution let us know.
Cheers