Modal is the version of rayon that represents a significant evolution in the history of this fabric. It was first developed in 1951 in Japan, and in more than one way, modal rayon is nearly identical to viscose rayon. The modal rayon uses hardwood cellulose such as birch and oak. The production requirements are similar to viscose rayon, and the steps involve spinning reconstituted beech trees into cellulose fibers that are then woven into fabric. They are often blended with spandex to create a stretchy and comfy material, commonly used for making sportswear, underwear, T-shirts, and bed sheets.