zebra striping when set smooth

it renders this way when set solid.
http://russ.supernerd.com/blend/rimsolid.jpg
and like this when set smooth.
http://russ.supernerd.com/blend/rimzebra.jpg

if is showed you screenshots it would look like zebra stripes.
very annoying. i’ve deleted duplicates and ctrl+n for normals, but
it isn’t helping.

Go int edit mode and deselect all the verts and then select->non-manifold. If some verts become selected you probably have some interior faces which have to be deleted.

GreyBeard

It found some vertices that were non-manifold but do I really have to delete them? Ain’t there anything else i can do to fix? They are pretty important.

You don’t delete the verts – you delete the interior faces. You have some faces bridging across the inside of your object.

GreyBeard