Creating porcelain sculptures with intricate undercuts presents a unique challenge for artists and manufacturers: ensuring the glaze fits perfectly without cracking or peeling. The solution lies in a combination of material science, artistic skill, and precise firing techniques.

First, artists carefully select glazes with compatible thermal expansion rates to the porcelain body. Low-expansion glazes are often preferred to minimize stress during cooling. Manufacturers may also adjust clay compositions to better match the glaze's properties, reducing the risk of misfit.

For complex undercuts, applying thinner layers of glaze helps prevent pooling and uneven contraction. Some artists use multiple firings, starting with a lower-temperature bisque firing to stabilize the sculpture before applying and firing the glaze. Others employ spray-glazing techniques to ensure even coverage in hard-to-reach areas.

Advanced manufacturers sometimes incorporate computer modeling to predict how glazes will behave on sculptural forms with undercuts. This allows for preemptive adjustments in glaze formulation or application methods.

The final key is controlled cooling in the kiln. Slow, gradual cooling gives both porcelain and glaze time to contract at harmonious rates, preserving the sculpture's integrity and surface finish. Through these combined approaches, today's ceramic artists and manufacturers successfully overcome the glaze fit challenges posed by undercut designs.