overlay smart material bundle include 15 smart materials that function overlay on top of a base material for example thick snow smart material adds snow to a stone sculpture or a bench and etc. so this smart material layers are not independent material.

use case of this bundle can be listed in these categories:

moss
muddy
snow
mold
wetness
damage: holes ,cracks , scratches
rusted iron leaks

use with version 7.3 or higher