This is a tool to simplify the use of Matcaps inside 3dsmax.
Its very usefull for making quick previs, layout, testing shaders and colors before going into really building shaders and rendering.
You can put any matcap files in your own folder structure to browse them easily and search by name.
Apply them to selected objects and adjust their colors, rotate and flip, adjust shadow intensity...etc
This tools has been made possible thanks to the viewport improvements and the OSL implementation inside 3dsmax.