How do mass and empty space work together in sculpture?

In sculpture, mass and space are fundamentally inseparable, as every sculpture is a material object that occupies three-dimensional space. While they are distinct concepts, they work together in three primary ways:1

• Extension: The material components of a sculpture extend into or move through the surrounding space.1
• Enclosure: Sculptures may enfold or enclose space, creating hollows, cavities, or voids—sometimes called "negative volumes"—that are as essential to the design as the solid material itself.12
• Relation: The various parts of a sculpture relate to one another across the space they occupy.1

The balance between these elements varies by artistic intent. Some sculptors prioritize mass, focusing on solid, space-occupying bulk, while others reduce mass to a minimum to emphasize movement through space or the creation of voids. In many modern works, mass and space are treated as equal partners, where the interplay between solid forms and the surrounding environment defines the viewer's experience. Ultimately, the surfaces of a sculpture serve as the bridge between these elements, defining the internal structure of the mass while simultaneously interacting with external space.2