The horizontal doors used on closet sliding doors move along a track mounted overhead and a floor guide for stability. To manage the smooth movement they‘ll have cushions and buffers on the ends to prevent damaging adjacent construction to ensure a smooth gliding motion when operated. Closet sliding doors of the vertical variety are seated in a groove, much like dresser drawers to ensure they glide in one direction.
These designs can be changed in several different ways. Just like a car, doors come with options that a consumer must choose from. The first and most basic choice is the size of the door. Doors come in sizes ranging from 30" wide to 80" tall as a standard size and increase to 60" wide and 96" tall. Anything above the standard is considered a custom door and may increase the cost of the door. Thickness can also vary from 7/8" to 1-3/8".
The Japanese may actually be the first people to use what we refer to today as sliding closet doors. These doors essentially follow the commonly accepted definition of a door that moves sideways or in an up and down motion. They still serve the same purpose as they did then, to manage space, provide ease of use and highlight or disguise internal or external features of a structure.