Most constructs are made of inorganic material, such as metal. Wooden constructs are an exception to this, made of vines twisted together into humanoid shape, or thick knots of petrified wood smoothly carved and assembled, or compacted dirt held together by the roots of interwoven flowers.

Some constructs are initially created as Wooden Constructs. Others, however, choose to convert to this material, enlisting the aid of mages and engineers in order to transfer their soul into a more organic vessel. They might seek to become closer to the natural world, or further remove themselves from the cold and unfeeling nature of Mechanus, or decide it is easier to inhabit a new form than to runically or mechanically alter their existing one.