Why Designers Use Drawings
Drawings, either manual or CAD, are used to:
- Exploration: Visualising initial ideas and concepts.
- Refinement: Iterating and improving designs.
- Communication: Conveying ideas to stakeholders, including clients, engineers, and manufacturers.
Drawings can be informal (e.g., free-hand sketches) or formal (e.g., orthographic projections), each serving different purposes in the design process.
Informal Drawing Techniques
Freehand Sketching
- Informal, fast drawings to visualise ideas
- Used in the early concept stage
| Advantages | Disadvantages |
|---|---|
| Speed: Allows rapid visualization of concepts. | Lack of Precision: May not accurately represent dimensions or proportions. |
| Flexibility: Encourages creativity without technical constraints. | Limited Detail: Often lacks the detail needed for technical analysis. |
| Accessibility: Requires minimal tools, just a pen and paper. |
Formal Drawing Techniques
Orthographic Projection
- Orthographic projection involves creating multiple views of an object (e.g., front, top, side) to represent its dimensions accurately.
- They are essential for manufacturing, as they provide the detailed specifications needed for production.
- Used for final design communication.
| Advantages | Disadvantages |
|---|---|
| Precision: Provides exact measurements and dimensions. | Complexity: Requires skill and experience to create accurately. |
| Comprehensiveness: Offers a complete view of the object from different angles. | Interpretation: Can be difficult for non-technical stakeholders to understand. |
- Orthographic drawings use projection symbols to indicate whether they follow:
- first-angle
- third-angle projection.
- These symbols help engineers and manufacturers interpret the layout of views correctly.
- First-angle is most commonly used in Europe, with third-angle used in UK and USA.
- The IB uses third-angle projection as standard.
Key Elements of an Orthographic Drawings
- Title block (with student/designer name, scale, date, drawing number)
- Third-angle projection symbol
- Front, top, and side views (typically three views, aligned correctly)
- Dimensions (clearly labelled with consistent units)
- Scale (noted in the title block or near the drawing)
- Hidden lines (to show features not visible from that view, such as dashed lines)
