3.1 Conceptual modelling 

• A conceptual model originates in the mind and its primary purpose is to outline the principles, processes and basic functions of a design or system.

• Designers use conceptual modeling to assist their understanding by simulating the subject matter they represent.

• Designers should consider systems, services and products in relation to what they should do, how they should behave, what they look like and whether they will be understood by the users in the manner intended.

What is the role of conceptual modelling in design?

• A conceptual model originates in the mind and its primary purpose is to outline the principles, processes and basic functions of a design or system.

• Conceptual models are used to help us know and understand ideas.

• Concept models are useful for communicating new ideas that are unfamiliar to people.

How do conceptual models vary in relation to the context? What are some of the conceptual modelling tools and skills needed?

• Conceptual models may vary in range from the more concrete, such as mental image that appears in mind, to the abstract mathematical models that do not appear directly in mind as an image.

• Conceptual models also range from scope of the subject they are representing. For example, they can represent either a single model (Statue of Liberty), whole classes of things (f.e. electron) or even a vast domains of subject matter, such as physical universe.

• Conceptual models are used to help us know and understand, design thinking, ideas, casual relationships, principles, data, systems, algorithms or processes.

• Graphical Modelling

  • Sketches

  • Drawings

  • Flow charts

• Physical Modelling

  • Card

  • Clay

  • Rapid prototype (3D printing)

  • Balsa wood

  • Blue styrofoam

• Virtual Modelling

  • Computer-Aided Design (CAD) Surface or Solid modelling, FEA, Data modeling

What is service design?

• Service design is the activity of planning and organizing people, infrastructure, communication and material components of a service in order to improve its quality and the interaction between service provider and customers. The purpose to design according to the needs of the customers → so the product is user-friendly, competitive and relevant.

How are conceptual models used to communicate with oneself and others?

• Concept models are used to communicate ideas that might be difficult to imagine otherwise. Designers use conceptual modelling to visualise and communicate ideas by simulating what they want to design.

The advantages of using conceptual modelling are:

1. Shares the "Big Picture": Conceptual models provide an overview, helping everyone understand the broad scope and goals.

2. Accessibility: They make it easier for non-designers and non-technical people to grasp complex ideas.

3. Improved Communication: Conceptual models facilitate better communication with clients and users.

4. Feedback: They allow designers to gauge people's reactions to concepts or ideas.

The disadvantages of using conceptual modelling are:

1. Lack of Detail: Conceptual models may not include all the intricate details necessary for final design.

2. Risk of Misinterpretation: These models can be misunderstood if not properly explained.

3. Scale Issues: Scale models can be misleading, especially when the final product size is significantly different.

4. Material Emulation: It can be difficult to emulate the final choice of materials in the conceptual model, which might affect the perception of the final product.

3.2 Graphical modelling 

• Graphical models are used to communicate design ideas. They simplify data and present it in a way that aids understanding and further development or discussion. Designers use graphical modelling to explore creative solutions and refine ideas from the technically impossible to the technically possible, within the constraints of feasibility.

• What is a graphical model? A graphical model is a 2D and 3D visualization of an idea, often created on paper or through software. They are drawings that convey the designer's idea.

• Perspective drawings Perspective drawings are used to show what a product will look like when finished in a more lifelike way. This informal drawing technique focuses on the 3D view of the design, with the lines of the perspective drawing heading towards a vanishing point.

• Isometric drawings Isometric drawings are used to accurately depict what a product will look like when finished. You can recognize these drawings by the angle of the object in the drawing, which is typically 30 degrees.

• Orthographic Projection Orthographic projection involves drawing a 3D object from different directions—usually the front, side, and plan views are drawn so that a person looking at the drawing can see all the important sides. These drawings are particularly useful when a design is almost ready for manufacture, as they must always have at least three views.

• Scale drawings Scale drawings are techniques that show an object in proportion to its actual size. They are used when something needs to be presented accurately, either for planning or manufacturing.

Sketching versus formal drawing techniques:

Sketching:

• Description: Spontaneous and free-hand representation used very early in the design process, usually free-hand.

• Advantages: Communicates ideas quickly among colleagues.

• Disadvantages: Cannot take the idea to manufacture.

Formal drawings:

• Description: Ruled out and accurate drawings used in the development phase of a design process. Represent a more resolved idea for further investigation.

• Advantages: Show details of the concept, can be used for construction, are accurate, and offer different views of objects that 3D drawings cannot provide.

• Disadvantages: Time-consuming, require high skill levels, and need specialist drawing equipment.

Part drawings:

• Description: Provide the information to assemble a product similarly to assembly drawings, with the added benefit of a list of parts (LOP) or Bill of Materials (BOM). Drawings of individual parts help indicate which part is broken and how to repair it.

Assembly drawings (Exploded isometric):

• Description: Show how parts of a product fit together, often used for model kits and flat-pack furniture. There are two types:

  • Fitted assembly drawing: Shows the parts put together, in 2D or 3D.

  • Exploded assembly drawing: Shows parts separated but in the correct relationship for fitting together, usually in 3D.

Algorithm

• An algorithm, in mathematics and computer science, is a self-contained step-by-step set of operations to be performed. This is often represented using a flow chart, which visually depicts the sequence of steps and decisions involved in the process.

3.3 Physical modelling 

Physical Modelling:

• Definition: A physical model is a three-dimensional, tangible representation of a design or system, often referred to as an "Appearance Model."

• Examples/Advantages:

  • Allows users to visualize the product and identify any problems easily.

  • Helps users understand how the product would look in a real environment.

• Disadvantages:

  • Time-consuming to create.

  • Cannot be manipulated the same way as digital models.

Scale Models:

• Definition: A scale model is a smaller or larger physical copy of an object, usually represented at a specific scale (e.g., 1:100).

• Examples/Advantages:

  • Easier to overview, especially if the original design is large.

  • Provides an idea of how large the model will be when it is actually produced/built.

• Disadvantages:

  • Time-consuming to create perfectly.

  • Difficult to show how it works beyond visual representation.

Aesthetic Models:

• Definition: Developed to look and feel like the final product, used for ergonomic testing and visual appeal evaluation.

• Examples/Advantages:

  • Useful instead of digital models for user visualization.

  • Helps production engineers assess feasibility.

• Disadvantages:

  • Non-working models.

  • Expensive due to the need for a realistic surface finish.

Mock-ups:

• Definition: Used to test ideas, either at scale or full-size, to gain feedback from users.

• Examples/Advantages:

  • Useful for getting user feedback.

  • Offers a full-size representation of the product.

• Disadvantages:

  • Less functionality than a prototype.

  • Can be difficult and time-consuming to create.

Functional Prototypes:

• Definition: A sample or model built to test a concept or process, representing a real, working product.

• Examples/Advantages:

  • Fully functional, used to test product functions.

  • Can be used to see how the product works in a real environment.

• Disadvantages:

  • Expensive to make.

  • Does not take aesthetics into account.

Fidelity:

• Definition: A measure of the realism of a model or simulation, ranging from low (conceptual) to high (mock-up of the idea, close to the final product).

• Contexts:

  • Restricted, general, partial, and total user and environment.

• Advantages:

  • Validates ideas and provides insight for development.

Instrumented Models:

• Definition: Physical models equipped to take measurements for quantitative feedback.

• Examples/Advantages:

  • Accurate measurements related to performance.

  • Records dynamic behavior in controlled environments.

• Disadvantages:

  • Time-consuming and expensive to set up.

3.4 Computer-aided design (CAD)

CAD and Modelling Techniques

• Computer-aided design (CAD) is used for generating, creating, developing, and analyzing designs using computer software. It enhances the whole design cycle, from data analysis to final designs.

CAD

• Definition: Used for conceptual design and layout, reducing testing and manufacturing costs.

• Advantages: Accurate, cost-effective design and analysis.

• Disadvantages: Requires software and training.

Surface Modelling

• Definition: Photo-realistic images of a product without internal data.

• Advantages: Realistic images.

• Disadvantages: No internal data.

Solid Modelling

• Definition: Clear representation of the final product, including internal dimensions.

• Advantages: Complete data for realization.

• Disadvantages: Requires detailed input.

Data Modelling

• Definition: Determines structure of data, including statistical models.

• Advantages: Organizes and structures data effectively.

Virtual Prototyping

• Definition: Uses surface and solid modelling for photo-realistic, interactive models.

Bottom-Up Modelling

• Definition: Parts are created independently and assembled later.

• Advantages: Independent part design.

• Disadvantages: Assembly can be complex.

Top-Down Modelling

• Definition: Design starts as a concept and evolves, with components designed to meet criteria.

• Advantages: Integrated design process.

• Disadvantages: Can be restrictive in design changes.

Digital Humans

• Definition: Computer simulations of human aspects for interaction with prototypes.

• Advantages: Quick iterations, accurate human requirements.

• Disadvantages: High complexity.

Motion Capture

• Definition: Recording of human and animal movement to create digital models.

• Advantages: Reduces animation costs, natural movements.

• Disadvantages: Limited to certain motions.

Haptic Technology

• Definition: Provides user sense of touch through mechanical feedback.

• Advantages: Improved user performance, better product design.

• Disadvantages: Expensive and complex.

Virtual Reality (VR)

• Definition: Simulates real situations for interaction.

• Advantages: Realistic simulation.

• Disadvantages: Requires VR setup.

Animation

• Definition: Links graphic screens to simulate motion.

• Advantages: Visual simulation of processes.

• Disadvantages: Requires animation software.

Finite Element Analysis (FEA)

• Definition: Simulates unknown factors in products.

• Advantages: Shows structural load, aerodynamics.

• Disadvantages: Requires specialized software.

3.5 Rapid prototyping 

Stereolithography (SLA) (uses laser or light to set plastic liquid)

• How it works: It is a form of 3D printing using a liquid bath of resin combined with an ultraviolet laser. The ultraviolet light hits the liquid, hardening it to form the structure of the object being printed. The base plate of the bath then moves down, allowing more liquid to flow over the previously hardened liquid so the same process can be repeated until the object being printed has been completed. The ‘Sweeper’ seen in the image to the right just helps even out the height of the bath every time the laser fires.

Laminated Object Manufacturing (LOM)

• How it works: It takes the sliced CAD data from a 3D model and cuts out each layer from a roll of material using a laser or plotter cutter. These sliced layers are glued together to form the model, which is either built on a movable platform below the machine or on locating pins when using card.

Fused Deposition Modelling (FDM) (Same as school makerbot and Flashforge)

• How it works: Uses an “additive” principle by laying down materials in layers. Plastic/metal is unwound from a coil and sent to an extrusion nozzle that can turn the flow on and off. The nozzle is heated to melt the material, and the nozzle moves in horizontal and vertical directions by a numerically controlled mechanism (CAM).

Selective Laser Sintering (SLS) (uses laser to set plastic powder)

• How it works: It is an additive manufacturing technique that uses a high-power laser (for example, a carbon dioxide laser) to fuse small particles of materials such as plastic, metal (direct metal laser sintering), ceramic, or glass powders into a mass that has a desired 3D shape.

Advantages and Disadvantages of Rapid Prototyping

Advantages:

• Decrease development time

• Decrease costly mistakes

• Increase number of variants of product (since each printed model takes less time to produce, the time saved can be used to develop more ideas, thus increasing productivity).

• Increase product complexity (more complex and difficult shapes can be modeled, which would perhaps not be possible with hand. For example, sculpting out an accurate sphere in a material).

• Increase effective communication (since the model is tangible, various aspects of the design would be easier to explain to others, as compared to CAD).

• Models can also be tested, which probably would only be possible through artificial simulation for CAD designs, and thus unlike prototypes, this would only give an approximate idea.

• Rapid Prototyping can provide concept proof that would be required for attracting funds (easier to explain, aesthetics can be focused on).

Disadvantages:

• Some people are of the opinion that rapid prototyping is not effective because, in actuality, it fails in replication of the real product or system.

• It could so happen that some important developmental steps could be omitted to get a quick and cheap working model. This can be one of the greatest disadvantages of rapid prototyping.

• Another disadvantage of rapid prototyping is one in which many problems are overlooked, resulting in endless rectifications and revisions.

• One more disadvantage of rapid prototyping is that it may not be suitable for large-sized applications.

• The user may have very high expectations about the prototype’s performance and the designer is unable to deliver these.