It is a Unity project that display how to build the avatar equipment system in Unity.
Equipment system is very important in the Game, specially in MMO Game.

Normally, equipment system contains tow important parts. 
Since the appearance of equipments are different(the mesh are different), so to merge these meshes together is necessary. 
Second, after merge meshes, the new mesh contains many materials(in this project, it has 4 material), that means it has at least 4 drawcalls(depends in the shader).
So to merge materials together will reduce drawcalls and improve game performance.