Shawn - Bryon was stating the problem of making a wrapper for a tank car
that curved evenly - that embossing the rivets or casting them on a
cast-resin wrapper made the overlay bend in a series of short tangents - if
I remember what he said.
My point is that using thick ink, it might be possible to print a
three-dimensional shape deep enough for a rivet. On a black tank car it
would be as visible as any rivet is (assuming it worked).
- John