Design and Applied Technology | Technical visualisation

Design & Applied Technology Study Notes: Technical Visualisation

Hello! Welcome to the exciting world of Technical Visualisation. Think of this chapter as learning the secret language of designers and engineers. It's all about taking an idea from inside your head and putting it onto paper or a screen so that other people can see it, understand it, and even build it. It’s a super important skill, whether you're designing a new phone, a cool piece of furniture, or even a video game character. Let's get started!

Part 1: The Foundation - Drawing to Communicate

Before we jump into fancy computer software, we need to understand the basics. At its heart, visualisation is about communication. These are the fundamental ways designers do it.

Pictorial Drawings: Making it look 3D!

A pictorial drawing is any drawing that shows an object in a 3D-like way on a 2D surface (like paper). The goal is to make it look realistic and easy to understand at a glance.

• Perspective Sketches: This is the most common type. It's how our eyes naturally see the world. Think about looking down a long, straight road – the sides of the road seem to get closer together in the distance. That's perspective!

Real-world use: Architects use perspective sketches to show clients what a new building will look like. Interior designers use them to plan out a room's layout and feel.

Engineering Drawings: The Blueprint for Building

While perspective drawings are great for showing what something looks like, they aren't precise enough for manufacturing. For that, we need Engineering Drawings. The most important type is Orthographic Projection.

Don't worry if this seems tricky at first! Here's a simple way to think about it:

Imagine you have an object (like your phone) inside a clear glass box. You look at the object from three specific directions and trace what you see onto the glass:

1. Front View: Look straight at the front of the object.
2. Top View: Look straight down from the top.
3. Side View: Look straight at the side.

Then, you unfold the box. The three flat drawings you are left with are the orthographic views. They show the object's true size and shape without any distortion.

Other important types of engineering drawings include:

• Assembly Drawing: Shows how all the different parts of a product fit together.
• Sectional Drawing: A "slice" through an object to show what's going on inside.
• Detail Drawing: A close-up view of a small, complex part with all its dimensions.
• Dimensioning: Adding measurements (length, width, height, etc.) to the drawing so a manufacturer knows exactly what size to make everything.

Standards and Conventions: The Universal Language

To make sure an engineer in Hong Kong can understand a drawing made by a designer in Germany, everyone agrees to follow a set of rules. These standards and conventions dictate things like what type of line to use for hidden details, how to write dimensions, and what symbols mean. It's like grammar for technical drawings!

Data Presentation: More than just objects

Visualisation isn't just for products. It's also for communicating data and ideas clearly. This includes:

• Charts and Diagrams: Like bar charts or flow charts to explain a process.
• Logos and Symbols: Simple graphics that convey a brand or an instruction (like a recycling symbol).

Key Takeaway: Manual drawing is the foundation. Pictorial drawings (like perspective) are for showing an idea quickly. Engineering drawings (like orthographic) are for precision and manufacturing.

Part 2: Bringing Drawings to Life

Adding Visual Impact to Graphics

A simple line drawing can be boring. To make it more appealing and easier to understand, designers use enhancement techniques. This is especially important for presentations, advertising, and packaging.

• Colouring: Adds emotion and helps differentiate parts.
• Shading & Highlighting: Creates the illusion of light and shadow, making a 2D drawing look 3D and solid.
• Rendering: A term for applying textures, materials, shadows, and reflections to make a drawing look as realistic as possible – almost like a photograph.

Physical Models & Prototypes

Sometimes, a drawing isn't enough. You need to hold the idea in your hands! That's where physical models come in.

• What are they for? To test ergonomics (how it feels to hold/use), check appearance, and see if parts fit together correctly.
• Common Materials: Cardboard, medium density fibreboard (MDF), high density foam board (HDFB), acrylic, and simple metals.
• Techniques: This can range from simple mock-up fabrication (like a cardboard model of a phone) to more complex prototyping.

Quick Review: Physical vs. Visual Models

Physical Models (Prototypes)
• Pros: You can touch and feel them, great for testing ergonomics, finds real-world problems.
• Cons: Can be expensive and time-consuming to make, difficult to change.

Visual Models (Drawings/Sketches)
• Pros: Quick and cheap to create, very easy to modify and explore different ideas.
• Cons: You can't physically test them, might not show unexpected problems.

Key Takeaway: Enhancing drawings with rendering makes them look realistic. Physical models help you test an idea in the real world before you spend a lot of money on manufacturing.

Part 3: The Digital Age - Computer-Aided Design (CAD)

Computer-Aided Design (CAD) is software that lets designers create incredibly detailed 2D and 3D models on a computer. It has revolutionised the design industry!

2D CAD vs. 3D CAD

• 2D CAD: Think of it as a digital drawing board. It's used for flat drawings like orthographic projections, electrical diagrams, and floor plans.
• 3D CAD: This is where you build a complete virtual object inside the computer. You can spin it around, look at it from any angle, and even see inside it.

A Crucial Concept: Vector vs. Raster Graphics

This is a super important difference to understand in digital design!

• Vector Graphics: The computer stores this as a mathematical formula (e.g., "draw a red line from point A to point B"). Because it's a formula, you can scale it up to the size of a building or down to the size of a pinhead, and it will never lose quality. It will always be perfectly sharp.
Used for: Logos, fonts, technical CAD drawings, laser cutting files.

• Raster Graphics (or Bitmap): This is an image made up of a grid of tiny coloured squares, called pixels. A photograph is a perfect example. If you zoom in too much or try to make it bigger, you'll start to see the individual pixels, and the image will look blurry or "pixelated".
Used for: Digital photos, scanned images, realistic digital paintings.

Common Mistake to Avoid!

Never design a company logo as a raster image (like a JPEG). If the company wants to print it on a huge billboard, it will look terrible! Logos should always be created as vector graphics so they can be scaled to any size.

The Superpowers of CAD

Using CAD gives designers amazing abilities that were impossible with just pen and paper.

• Virtual Prototypes: You can build and test your design on the computer before ever making a physical object. This saves a huge amount of time and money.
• Simulation and Analysis: CAD software can test your virtual model for you!
   - Structural Analysis: How much force can it take before it bends or breaks?
   - Mass Property Analysis: How much will it weigh? Where is its centre of gravity?
• Easy Modification (Parametric Design): This is like magic. You can link dimensions together. If you change the height of your model, the width can automatically adjust to keep the right proportions!
• Data Transfer to CAM: You can send your finished CAD file directly to a manufacturing machine, like a 3D printer or a CNC laser cutter, to have it made automatically. (CAM stands for Computer-Aided Manufacturing).

Did you know? The very first CAD system, called "Sketchpad," was invented in 1963 at MIT. It was the first program that allowed a person to interactively draw on a computer screen using a "light pen"!

Real-World Applications of CAD & Visualisation

CAD is used everywhere! Here are just a few examples:

• Animation & Movies: All the characters and environments in a Pixar movie are complex 3D CAD models. They use techniques like 3D scanning and motion capture to make things look realistic.
• Logistics: Companies can use CAD to simulate the layout of a factory or warehouse to find the most efficient way to arrange machines and move goods.
• Architecture & VR: Architects design buildings in CAD and then use Virtual Reality (VR) to let clients "walk through" the virtual building before it's even built.
• Product Design: Nearly every product you own, from your shoes to your games console, was designed and refined using CAD software.

Key Takeaway: CAD is the ultimate tool for modern designers. It allows for the creation of precise virtual prototypes that can be easily tested, modified, and sent for manufacturing, completely changing the design process.