Historically, the sculpture was defined as three-dimensional representational art. In recent decades, ideas about this art form have evolved, and, among other things, it no longer needs to be representational.

Materials

Sculptures can be made from hard materials, like stone or more malleable materials that are easier to shape. Artists have used various materials over the years, including clay, plaster, wax, metal, fabric, glass, wood, and rubber. While many people may think of sculpture as molded clay or chiseled stone, the reality is that many other techniques may be used, including carving, casting, sewing, and welding. 

Traditionally, materials were all natural and included ivory, bone, and clay. Newer materials and newer techniques have broadened both the materials used and the means of production.

Form

Sculpture is commonly thought of as freestanding 3D pieces, but bas relief, tableaux, and larger pieces that enclose the viewer are other formats. Historically, it was accepted that sculpture did not move, but this is no longer true.

Freestanding objects are often displayed on a pedestal with the intent to view them in the round. Bas relief cannot be displayed in this manner as it is part of a surface, often a wall. It projects out from the surface into space but does not stand independently, and there is no means to view it in the round.

In the twentieth century, some artists used plastic sheets and metal rods to enclose space as a primary purpose of their work. It was intended to be experienced from the inside, similar to how humans move through spaces created by the art of architecture, but solely for artistic purposes.

Accessibility

Because sculpture is three-dimensional, it is an art form that can be experienced by touch. This means it is something visually impaired individuals can appreciate in the way they cannot appreciate 2D art forms like painting.

Some people have even argued that sculpture should rightly, first and foremost, be viewed as a tactile experience, not a visual one. As such, it has the potential to create a powerful and deep experience.