TF-Shell: Facilitating Physical Deformation with Iterative and Shape Memory Thermoforming for 3D Printing

Prototyping with 3D printing depends heavily on virtual modeling, which requires expertise and often leads to scale mismatches and inefficient iteration. Physical deformation through heating is possible but challenging, as heating is difficult to control and deformation remains complex. We introduce TF-Shell, a thermoformable shell that enables repeatable, localized thermoforming of 3D-printed prototypes. Leveraging shape-memory properties, TF-Shell allows 3D-printed objects to achieve volumetric deformation, restoration, and shape memorization within the physical prototyping process. With customizable features, it can be embedded into free-form models through a design tool. A user study shows that TF-Shell provides intuitive, convenient physical modification and expands iteration beyond virtual modeling. Technical evaluations confirm its thermoformability and repeatability, establishing TF-Shell as a practical approach for integrating physical deformation into 3D printing workflows.