3.3 Physical modelling
Essential Idea
A physical model is a three-dimensional, tangible representation of a design or system.
Nature and Aims of Design
Nature of design
Designers use physical models to visualize information about the context that the model represents. It is very common for physical models of large objects to be scaled down and smaller objects scaled up for ease of visualization. The primary goal of physical modelling is to test aspects of a product against user requirements. Thorough testing at the design development stage ensures that an appropriate product is developed. (1.2, 1.13, 3.2)
Aims
Aim 4: Physical modelling not only allows designers to explore and test their ideas, but to also present them to others. Engaging clients, focus groups and experts to interact with physical models of products allows designers to gain valuable feedback that enable them to improve the design and product-user interface.
Guidance
As a DP Design Technology student, you should:
understand the various applications of physical models and how and why a designer might use these models to gain a better understanding if the design context.
be able to use instrumented models to measure the level of a product's performance and facilitate ongoing formative evaluation and testing. This testing and evaluation should be used to further develop and refine your design.
Identify the advantages and disadvantages of physical models
Related topics and resources
(non-IB content)
In your Criterion B of your IA, physical modeling plays an important role in testing and verifying your idea.
Concepts and principles:
Designers use physical models to obtain information about various aspects of a design context. They are particularly useful in understanding how an object will be physically manipulated or used by a user. They can provide important information about:
Ergonomics and fit: The model can show how the design will fit to the user's body or held in the user's hand.
Relationships between the internal structure and external structure: For example, how the electronic components of device might influence the external structure of a design, and vice versa. This could include the placement of ports, switches, buttons, grips, etc.
Aesthetic considerations: Form, scale, shape, texture, and color can all be explored through creating a physical model.
Examples of prototype handles that were used by the designers and users to refine the handle design. Learn more in this OXO Good Grips case study and in Topic 7.1 User Centered Design
Scale models
A scale model a model that is either a smaller or larger physical copy of an object. Scale models are often used in architecture, where smaller models of a building are presented. This smaller model helps the architect communicate to the client or team members the aesthetic, form, proportion, and functional elements of a building.
Scale models are also used in some testing situations when it is financially or practically impossible to test a full-scale model. An example of this would be a wind tunnel testing a scale model of an aircraft.
Scale models are advantageous for communicating the form, thinking, aesthetics or ideas behind a design.
Architecture Model - Denmark Frederiksberg Courthouse, source
Aesthetic Models
An aesthetic model is a model developed to look and feel like the real product. They are used to evaluate user appeal or in ergonomic testing. These models do not actually work and are typically not intended to be handled greatly. The primary function is to communicate and test the aesthetic elements of a design. In addition to being used to communicate and evaluate how a design looks and appeals to a user, aesthetic models might also be used to evaluate the properties of a material:
Weight and balance: using materials similar in weight and density to the final production material, the model could be used to evaluate how heavy a design is, or how it balances. A good example of this might be a hand tool, portable device, or sports equipment.
Texture and surface qualities: finishes, paint, or textures might be applied to the surface to communicate how the the surface looks, feels, or reflects light.
Clay modeling is a techniques used in car design to visualize and communicate the form of the car.
Mock-ups
A mock-up is a scale or full-size representation of a product used to gain feedback from users. They have some functionality, meaning that they can also be used as a prototype. Mockiups are essentially used to test ideas, and are often used to show how something works or feels.
Successful IAs use prototyping to develop ideas, gather user feedback and test materials, processes, and function. Use the Criterion B stage of your IA inquiry to troubleshot and confirm your design specifications.
Prototypes
A prototype is a sample or model built to test a concept or process, or to act as an object to be replicated or learned from. Prototypes can be developed at a range of fidelity and for different contexts.
Prototypes can be used to test and refine specifications. They can also be used to help learn more about the design or manufacturing context. For instance, through building a prototype, the design might discover issues and challenges related to manufacturing the product.
Fidelity of prototypes
The fidelity of the prototype is the degree to which the prototype is exactly like the final product. Prototypes can be made at different levels of fidelity, depending on the application and context.
Prototypes are often put in the hands of users so that designers can observe how they are used. In this way, designers can gain feedback from the users, and learn more about the design context.
Examples of different prototypes for a Dyson vacuum.
Low-fidelity models are a conceptual representation analogous to an idea. They are not tangible or durable, but they do communicate basic information about form, shape, function, etc. Paper prototypes are a good example of low-fidelity prototypes
Mid-fidelity prototypes communicate more about an idea or concept. They may communicate some but not all of the functions of the design.
High-fidelity prototypes attempt to represent as close as possible the functionality of the final product. They are typically durable enough to be testable and used by the user group to gather usability data.
Instrumented models
Prototypes that are equipped with the ability to take measurements to provide accurate quantitative feedback for analysis. Essential, they are models that equipped with sensors or other types of measuring systems that can record data. This data is then used to evaluate the performance of the product, mechanism, or material, as well as to understand better how the user might use the product.
In the examples below, you can see how car designers and manufacturers use different types of instrumented models to better understand car performance and improve driver and pedestrian safety.
Advantages and Disadvantages of Physical Models
Advantages
Explore and test ideas: another form of exploration of design ideas; Some ideas are more easily explorable in physical form compared to other modeling forms (e.g. a flat pack container that is folded out of a single sheet of material)
Easily understandable: a physical representation of an idea, concept or design.
Communication: Allow for clear communication with clients and team members about the design. This is especially important when communicating with a non-technical audience
Tangible: it can be put in someone's hands or tested
User testing: Can be easily used in user tials to generate data; Particularly useful when gathering ergonomic data
Disadvantages
Accuracy: Designers could mistakenly assume that the model accurately represents the reality of the design context. For example, a scale model might not accurate communicate ergonomic information. However, careful analysis and inquiry can avoid or lessen this.
Time consuming; creating models, and iteration of the models, can be time consuming
Cost: The manufacturing of prototypes can add to the overall cost of the manufacturing the design.
Materials: In many cases, the material used in the model is not the same as the material used in the final product. As such, accurate data about the performance or aesthetic qualities of the product may not be gathered
Environmental cost: Materials and processes used may produce waste or use raw materials that impact the environment.
Skill: Requires a level of skill, depending on the application. The model maker would need to be familiar with the materials or technology used to manufacture the model.
Comparison of Types of Physical Models
Type of Physical Model
Aesthetic Model
Advantages
Look like the final model
Evaluate aesthetic appeal
Use Cases
Use to consider color combinations, textures, form, etc.
Get client feedback on aesthetic aspects of a design
Mock-up
scaled or full-size replica
communicate form and proportion of a design
Low-fidelity models can be made relatively quickly
Used to gather client feedback
Prototypes
Validate that a design can work as intended
User testing of functionality
Develop and improve the functionality of a design
Instrumented Models
Provide accurate quantifiable data about a design as it is being used or tested
Can provide data in real-time
Understand how physical forces act on a design
Allow for very precise measurement
Evaluate how a design performs under various conditions and forces
Test performance of materials (i.e. impact testing, heat resistance, etc.)
Scale Models
Can be larger than the actual design and thus communicate fine details
Can be smaller than the actual design and thus save materials, time, etc, as elements of the design are developed
Used to gather client feedback about a design
If it is a small design like a watch, a large scale model can help communicate details that would otherwise not be easy to see
If it is a large design, like a car door, a small scale model can allow the designer to work out details of mechanism without having to invest time and money in producing a life-size model