Communicating and recording design ideas: sketching, projection and CAD

Welcome to Design Communication!

Ever had a brilliant idea in your head but struggled to explain it to someone else? That is exactly why design communication is so important! In this chapter, we will explore the different ways designers "record" their ideas—from quick sketches on a napkin to complex 3D computer models. These techniques help you develop your ideas, share them with clients, and eventually give a manufacturer the instructions they need to build the real thing.

1. Freehand Sketching and Annotation

The first step in any design journey is usually a freehand sketch. This means drawing without the help of rulers or technical equipment. It is all about speed and getting thoughts onto paper quickly.

• 2D Sketching: Flat drawings showing just one side of an object (like looking at a wall).
• 3D Sketching: Drawings that show depth, making the object look "solid."
• Annotated Sketches: This is a sketch with written notes. Annotations are vital because a drawing alone might not show what material a product is made of, how it moves, or what it feels like.

Quick Tip: When annotating, don't just label parts (e.g., "Plastic handle"). Instead, justify your choice (e.g., "Plastic handle because it is an insulator of heat and comfortable to grip").

2. Pictorial Drawings (3D Projections)

When we want to show a realistic view of a product, we use specific 3D drawing techniques. Each has its own "rules" regarding angles.

Isometric Projection

In Isometric drawing, all vertical lines stay vertical, but horizontal lines are drawn at an angle of \(30^\circ\).
Key Fact: This is very popular because the object doesn't appear distorted, and you can take measurements directly from the drawing.

Oblique Projection

In Oblique drawing, the front face of the object is drawn flat (2D), and the depth is added at a \(45^\circ\) angle.
Key Fact: It is quicker than isometric but can look a bit "unrealistic" because the side of the object appears too long.

Perspective Drawing

This is the most realistic-looking method. It uses vanishing points on a horizon line. Parallel lines appear to meet in the distance, just like a road narrowing as it moves away from you.
Key Fact: It is great for showing a client what a finished product will look like in real life, but you cannot use it to take accurate measurements.

Key Takeaway: Use Isometric for technical 3D info and Perspective for realistic 3D visuals.

3. Working Drawings (2D Projections)

Once the design is finalized, we need "blueprints" that provide exact details for manufacturing. These are usually 2D.

Orthographic Projection

This shows a 3D object as a series of 2D drawings. Usually, you provide three views:
1. Front View (The Elevation)
2. Side View (The End Elevation)
3. Top View (The Plan)
These are drawn to scale and include dimensions so the maker knows exactly how big to make the product.

Exploded Views and Assembly Drawings

Have you ever put together a piece of flat-pack furniture? The instructions usually feature an exploded view.
- An exploded view shows the product "taken apart" but with the components lined up so you can see how they fit together.
- An assembly drawing shows the product fully put together, often with "balloon" labels to identify different parts.

4. Specialist Diagrams

Sometimes, we don't need to see what a product looks like; we need to see how it works. For this, we use diagrams.

• System Diagrams: These use "input-process-output" boxes to show how a system functions without showing the actual components.
• Schematic Diagrams: Most common in electronics. They use standard symbols (like the ones for LEDs or Resistors) to show how a circuit is connected. They aren't drawn to scale; they just show the logical "path" of electricity.

5. Digital Media and 3D Models

Designers don't just use paper! Modern technology has changed how we record ideas.

Computer-Aided Design (CAD)

CAD uses specialist software to create 2D or 3D models.
Advantages:
- Accuracy: You can work to tiny fractions of a millimeter.
- Editing: It is easy to change a design without starting again.
- Sharing: Files can be emailed across the world instantly.
- CAM Link: CAD files can be sent directly to machines (like 3D printers or laser cutters) to be made.

Physical 3D Models

Before making a final product in expensive materials (like stainless steel), designers make "mock-ups" or prototypes out of cheap materials like cardboard, foam, or MDF.
Why? To check the scale, how it feels in the hand (ergonomics), and if the moving parts actually work.

Digital Photography and Media

Designers use digital cameras to record their progress. This is great for showing how a design evolved over time or for including real-world images in a digital portfolio.

6. Recording and Justifying Ideas

In your exam and your NEA (folder work), you must be able to justify your design. This means explaining why you made a choice.
Example: "I have used an exploded view to communicate my design because it clearly shows how the M4 screws fit into the pre-drilled holes, which is helpful for the person assembling the product."

Quick Review: Which drawing should I use?

- Need a quick idea? Freehand Sketch
- Need to show a client a realistic look? Perspective
- Need to show a maker the exact sizes? Orthographic
- Need to show how parts fit together? Exploded View
- Need to test a circuit? Schematic Diagram

Key Takeaway: Different communication methods serve different purposes. A good designer chooses the right tool for the right job!