Solidify modifier version 1.02 is a modifer plugin that takes your surfaces and makes them
solid. An easier way to describe it would be to say that it does extrusion
along vertex normals. No more wrestling with regular extrusion or double
sided materials, Solidify makes it a snap to give your surfaces thickness,
with as many segments as you need. Version 1.02 adds the ability to assign
different material ID's to newly created faces and fixes a couple of bugs.