What will be the result if the Shell command is used without selecting a piercing face?

When the Shell command is used in CAD software like NX, it is designed to create a hollowed-out version of a solid model. This process typically requires selecting faces that will act as piercing or opening surfaces. If a piercing face is not specified, the command cannot effectively determine where to create the hollow inner structure.

When the Shell command is executed without a selected piercing face, the software will interpret this as a request to hollow out the entire solid. As a result, the command produces a hollow solid body by removing material from the inside of the model while keeping the outer shell intact. This ensures the structure remains as a solid object but with its interior space created according to the specifications of the Shell command.

In this context, the function aims to keep the integrity of the design while allowing for the necessary modifications to achieve the desired hollow form. The output remains valid and complete, indicating that the operation yields a hollow solid body even without a designated piercing face.