Quote -
maybe an easier fix is to detach the top & bottom in your modeler?..as in this obj exported from 3dsmax,it;s still one mesh but the top verts aren't attached to the middle ones
http://stefan-morrell.com/cyl_test3.obj...

An added comment:

Splitting vertices is not always a good option.  For instance, if you try to put displacement maps on that cylinder, it's going to explode.  It also increases the size of the file.  For instance, that cylinder has 82 verts as it stands.  If I weld it back together, it only has 42 verts.  That's because the 40 additional vertices in the top and bottom (20 faced cylinder) are now combined with the face vertices.  Smaller model memory-footprint = always good.

Also, some distributors like DAZ don't appreciate split verts when it is used for correcting rendering problems.  They insist on people using additional edgelines to create sharp edges. 
Well, what if you had a model where you were trying to correct this artifact?  Instead of adding yet MORE geometry and/or removing the ability for you to use displacement maps and keeping any future user from adding their own displacement maps.. .all you might have to do is remap it using a Planar Projection!   Wouldn't that be nice?

Granted, this same technique may not apply to sharp edges.  Most likely, it doesn't as smooth-shading is NOT what we're looking at here.  At least, not in the classic sense.   But, having another tool that reduces the need for "corrective" geometry and gives consistent and very desirable results is always a "Good Thing."  If Planar Projections end up being the solution to these problems, a LOT of what people have been using as corrective geometry to fix this issue is going to disappear - All they'll need to do is Planar Project their UVMap and go from there.