A prototype is well established as a "design tool" for its key role in problem solving. Prototypes for industrial applications are well investigated and demonstrated. Prototype-making involves a lot of creativity in addition to the necessary skills and resources. With the advent of three-dimensional (3-D) CAD and 3-D printing, making prototypes has become somewhat effortless. Since the last decade, 3-D printed prototypes have been used for various healthcare applications. From published literature, we can see its applications are growing. Some of its applications include anatomical models for teaching, procedural planning, surgery guides, and implants. The medical image information obtained as DICOM data can be processed to integrate and regenerate the shape of anatomy. This forms the basis of medical 3-D virtual modelling and, subsequently, its fabrication using 3-D printing.

From our literature study, we see work on hard tissues while soft-tissue applications are sparse. This is due to certain challenges they pose in image processing. The current research study focuses on one of the soft tissue-based organs, namely, the heart. The motivation comes from the risks that the organ poses at birth, called Congenital Heart Disease (CHD). They are caused by the malformed heart during embryonic development in the foetus. Because defects occur at random, they manifest in a wide range of forms. Many of these minor defects resolve in early childhood. However, the severe and moderate defects need surgical interventions. Like any treatment, early detection helps plan treatment management. In most cases, neonatal echocardiography is the gold standard for assessing the condition. However, there are a few complexities that are hard to diagnose and plan corrective procedures for. The infant’s heart surgeries are generally risky, and planning such interventions on the operation table can be risky and can lead to the loss of precious time. In such cases, clinicians may study the digital models on a computer. The virtual 3D models can be zoomed in, panned, and rotated to explore. Surgeons are used to spatial visualization, where touch and feel are essential. With just the virtual models on screen, the rich heart morphology cannot be completely visualised. It is here that we see clinicians needing physical models for haptic exploration in true size and shape to plan interventional procedures. These physical models can be called patient-specific heart models. While the literature shows such applications, we observed a few gaps: absence of a standard workflow procedure to identify the nature of cases that demand models, how to accurately produce them, and how to evaluate their accuracy.