Graphical Modelling
- Graphical models are essential tools for communicating design ideas.
- They help designers explore possibilities, refine concepts, and present solutions effectively.
Graphical Models
Graphical Models: Visual representations used to communicate design ideas, explore solutions, and refine concepts.
The development of ideas through graphical models allows designers to explore and deepen their understanding of a problem and its context.
Sketching vs. Formal Drawing Techniques
- Graphical models are 2D representations used by designers to explore and communicate ideas.
- Different techniques help at different stages of the design process.
Sketching (Quick & Easy)
- Fast and rough – Used at the start of the design process.
- Explores many ideas quickly – Helps generate and refine concepts.
- No strict rules – Freehand drawings that focus on creativity.
- Communicates early thoughts – Helps share ideas with clients and the design team.
Example: A car designer quickly sketches multiple car shapes before choosing one to refine
Formal Drawing Techniques (Precise & Technical)
As the design develops, more detailed and accurate drawings are needed:
- Isometric Drawings – 3D-like drawings used to show depth and dimensions.
- Orthographic Drawings – Multi-view (top, front, side) diagrams that show exact measurements.
- CAD Renderings – Digital 3D models that provide a high-fidelity version of the design.
How designers communicate a 3D view of an object
- Orthographic drawings
- Isometric drawings
- Part and assembly drawings
Orthographic Drawings
- Orthographic drawings are technical 2D drawings that show different sides of an object without perspective.
- Instead of looking like a 3D sketch, they present flat views of each side (top, front, side) to give an accurate representation of the object's shape and dimensions.
- Features
- Show the "side" of a product – They display different views separately, such as the front, top, and side views.
- No vanishing point or perspective – Unlike 3D sketches, everything is drawn to scale without distortion.
- Accurate representation of form – They include exact dimensions and proportions, making them useful for manufacturing.
Applications of Orthographic Drawings
- Used in planning drawings – Helps designers communicate precise size, shape, and form before production.
- Essential for manufacturing – Factories and engineers use these drawings to build parts accurately.
- Standard in technical fields – Common in architecture, product design, and engineering.
Example
- Imagine designing a smartphone case
- An orthographic drawing would show:
- Front view (flat image of the front)
- Side view (thickness and shape from the side)
- Top view (how wide and deep it is)
- This ensures manufacturers know the exact dimensions to produce an accurate final product.
Isometric Drawings
- Isometric drawings are 3D-like drawings that show the shape and form of an object clearly.
- Unlike perspective drawings, they do not have vanishing points, meaning all sides remain at a consistent scale.
- Features
- No vanishing points – Objects don’t shrink or distort as they move further away.
- Drawn on a 30°/90°/30° grid – The horizontal edges are tilted at 30 degrees, while vertical edges stay at 90 degrees.
- Represents 3D objects accurately – It allows designers to show multiple sides of an object in a single drawing.
Applications of Isometric Drawings
- Used to communicate the overall form of a product – Gives a clear idea of how a design looks from different angles.
- Helpful in product and industrial design – Used by engineers, designers, and architects to visualize objects.
- Common in instruction manuals and technical drawings – Many assembly guides (e.g., LEGO or IKEA) use isometric drawings to show how parts fit together.
Example
- Imagine designing a chair
- An isometric drawing would show:
- Front, top, and side views in one image (without distortion)
- Accurate proportions and form
- Easy-to-read design for manufacturers
- This makes it a great way to communicate ideas clearly before moving to CAD modeling or physical prototypes.
Part and Assembly Drawings
- When designing complex objects with multiple components, part and assembly drawings help show how the pieces fit together.
- They are essential for manufacturers, engineers, and designers to understand the structure and assembly process.
Exploded Isometric Drawings
- An exploded isometric drawing is a special type of isometric drawing that shows how different parts of an object come together.
- The parts are drawn separately but in the correct order of assembly, making it clear how they connect.
- Features of Exploded Isometric Drawings
- Shows how an object is assembled – Displays parts in an exploded view to illustrate their relationships.
- Maintains isometric projection – No vanishing points, just like regular isometric drawings.
- Clearly communicates assembly sequence – Helps users understand the correct order of putting parts together.
A bicycle exploded isometric drawing might show the frame, wheels, chain, and seat as separate pieces floating apart, illustrating how they fit together.
Assembly Drawings
- Assembly drawings show how multiple components come together to form a finished product.
- They can be presented as exploded drawings or more compact, final views.
Features of Assembly Drawings
- Illustrates how a product is assembled – Can be exploded or show the fully built object.
- Includes names and numbers of parts – Helps identify each component.
- Contains a Bill of Materials (BOM) – A list that details all parts, materials, and quantities needed for production.
A car engine assembly drawing will label each part (pistons, spark plugs, cylinders) and include a BOM listing materials, screws, and tools required.
Perspective Drawings - Simple Explanation
- A perspective drawing shows an object as it would appear in real life from a specific viewpoint.
- It creates a sense of depth and space by using foreshortening and vanishing points to make objects look more realistic.
Features of Perspective Drawings
- Shows objects from a single viewpoint – Mimics how the human eye sees things.
- Uses foreshortening – Objects appear smaller as they get farther away.
- Includes vanishing points – Lines converge at one or more points on the horizon to create depth.
If you draw a long road, it will look like the two sides get closer together as they go into the distance.
Applications of Perspective Drawings
- Used in early design stages – Helps visualize how a design might look in a real setting.
- Common in architecture and product design – Makes sketches more relatable for clients.
- Familiar to most people – This is how we naturally see the world, making it easier to understand.
Architects use perspective drawings to show how a house or building will look from a person’s point of view.
Comparison of Different Graphical Models
| Model | Advantages | Disadvantages |
|---|---|---|
| Sketching | Quick, no tools needed | Lacks detail, may not represent the final product |
| Orthographic | Highly accurate, clear for manufacturing | Requires CAD skills, time-consuming |
| Isometric | Shows overall view, easily understood | Lacks detail, may not resemble the finished product |
| Perspective | Realistic, easily understood | Time-consuming, lacks accuracy, requires skill |
| Assembly | Clear for clients and manufacturers | Time-consuming, requires CAD skills |
Reflection
- What are the key differences between orthographic and isometric drawings?
- How do annotations enhance the effectiveness of graphical models?
- Why is it important to choose the right type of graphical model for a specific context?
