A solid-to-hollow evolution in macroscopic structure is challenging in synthetic materials. Herein we report a fundamentally new strategy for guiding macroscopic, unidirectional shape-evolution of materials without compromising the material’s integrity, based on the creation of a field with a “swelling pole” and a “shrinking pole” to drive polymers to disassemble, migrate, and resettle in the targeted region. We demonstrate this concept by using dynamic hydrogels containing anchored acrylic ligands and hydrophobic long alkyl chains. Adding water molecules and ferric ions (Fe3+) to induce a swelling-shrinking field transforms the hydrogels from solid to hollow. The strategy is versatile in the generation of various closed hollow objects including spheres, helix tubes, and cubes with different diameters, for different applications.