Soft mati?re occupies the history of a informal form in sculpture art. Soft mati?re creates its own flexible and informal form. An informal form is made by the environmental conditions of a place where works are placed and the acts applied to the materials. This accidental form is composed of ‘process’ which is made, or simultaneously transformed or becomes extinct in the current time. ‘Process’ is the result form accepting ‘hazard' which has been excluded in art as the parameters for creation. ‘Process’ transforms the definition of sculpture - permanent and definitive form - to a temporary and variable form. It creates new concept of sculpture ‘sculpture as process’ which is beyond the conventional definition of sculpture, completed objects. An informal form is made by an installation method. When a sculpture is placed on the floor, balance is obtained and when a sculpture is hung on the ceiling or the walls, an unplanned form is made by gravity. An informal form in which a production space becomes an exhibition space expands to an environmental space encompassing walls, air space, and ground, breaking from the limitation of a space, a pedestal, and dismantles the traditional construction method ‘vertical construction’. Thus, the sculptures formed by soft mati?re request artists for their exploration and understanding about potential expression, operating conditions for hazard, installation methods, and the environment of a place where the works are placed and ask questions about several conventions relating to sculpture art such as the emphasis of act, the involvement of spectators, and the collection and the preservation of works rather than the creation of objects, know-hows for producing forms, and the creation of forms.