Closed and Open Form
Definitions : One of the distinguishing concerns of 20th century sculpture was liberating three- dimensional form from being the closed, solid mass that was the pre-modern traditions of carved stone and modeled bronze. These new works focused on opening up the form and thereby freeing it from constraints of gravity and making it ëtransparentí so to reveal its internal structure. Closed and open form are, at best, relative terms which need to be defined by observing that various visual elements of a sculpture to see what sort of relationship is established between the sculpture and its ambient space.
http://www.smcm.edu/users/lnscheer/lecture%20web%20pages/208open/open.html