Four core approaches to predicting product performance include:

1. 1. 1. 1. 1. 1. 1. 1. Physical prototyping
                     2. Virtual prototyping
                     3. Mixed (hybrid) prototyping
                     4. DIY prototyping

1. 1. 1. 1. PHYSICAL PROTOTYPING

A physical prototype is an initial, tangible version of a product designed to test certain parameters or constraints. While invaluable, physical prototypes are typically costly and time-consuming to produce, often requiring multiple iterations to meet performance goals.

Although hand calculations have long been a staple of engineering, they lack the precision of modern simulation tools. They depend on broad assumptions and simplifications, making them suitable only for basic geometries and uncomplicated designs. Collaboration challenges also arise when using spreadsheets for calculations. As complexity and safety requirements increase, manual methods become less feasible.

1. 1. 1. 1. 2. VIRTUAL PROTOTYPING

Virtual prototyping simulates a product’s performance in a digital environment, creating a virtual representation of the design. Once restricted to specialists in large corporations — particularly in aerospace and automotive sectors — these tools are now more accessible to a wider range of designers.

Earlier tools offered only basic linear static stress analysis, but modern simulation software supports advanced capabilities such as:

• • • • Nonlinear static stress analysis
      • Dynamic stress (vibration) analysis
      • Fluid dynamics
      • Thermal analysis
      • FEA-based stress and motion simulations

Virtual Prototype Characteristics

A virtual prototype exists entirely on a computational platform, enabling detailed analysis and integration into manufacturing workflows. While simulations are limited to phenomena programmed into the software (potentially omitting some real-world factors), they provide valuable insight for complex design generation.

Compared to physical prototypes, virtual versions offer quicker testing, lower costs, and the ability to perform extensive parametric studies. They also facilitate collaboration across geographically dispersed teams.

Notably, studies indicate that virtual prototypes can match the performance of paper prototypes in usability testing, require less production effort, and are better suited to iterative design. Designers often combine virtual tools such as CAD for documentation with sketches for early ideation, avoiding unnecessary procurement of physical components.

1. 1. 1. 1. 3. MIXED (HYBRID) PROTOTYPING

Mixed prototyping integrates both physical and virtual components into a single model. This approach offers flexible configurations where components — and even users — can be either real or virtual.

It is particularly valuable for:

• • • • Usability testing in complex systems
      • Evaluating system dynamics with combined simulation and physical elements
      • Balancing different levels of fidelity between subsystems

Mixed prototypes are usually developed in later stages, once subsystem prototypes are complete and ready for integration. Decisions about which components remain physical or virtual depend on project objectives, constraints, and desired testing outcomes.

Prototype Embodiment and Construction

Guidance on the physical construction phase of prototypes is relatively scarce, largely because this stage is highly domain-specific. Nevertheless, several key principles apply broadly:

• • • • Build the minimum viable prototype to conserve resources.
      • Fewer parts often result in better performance.
      • The number of components in a prototype tends to grow steadily during development — minimizing part count enhances efficiency and performance.

1. 1. 1. 1. 4. OPEN-SOURCE AND DIY PROTOTYPING

The open-source movement has transformed prototyping by providing vast, freely accessible knowledge bases and tools. Communities such as Thingiverse, GitHub, and Instructables enable rapid, low-cost development by sharing designs, code, and fabrication techniques. Many projects benefit from the user also acting as the designer, ensuring a precise alignment with needs.

Resources include:

• • • • • • • • • Open-source component databases
                • Free CAD and modelling software
                • Affordable digital fabrication tools (e.g., 3D printers, laser cutters)
                • Distributed manufacturing networks
                • Modular electronics platforms (e.g., Arduino, Adafruit)

Similarly, the DIY movement has fostered extensive design repositories and low-cost construction techniques, such as:

• • • • • • • • • Repurposing commercial products for parts
                • Using basic craft techniques for simplicity
                • Employing stencils for precision
                • Standardizing manufacturing across parts
                • Incorporating lattice structures for strength and weight optimization