3.4 Computer-aided design (CAD) Notes

Computer-Aided Design (CAD)

2D Software (For Sketching & Presentations)

1. Purpose: Creates flat, 2D images used to communicate design ideas and refine concepts.
2. Examples: Adobe Illustrator, Adobe Photoshop
3. Use Cases:
   1. Digital product presentations (e.g., watches, fashion designs).
   2. Creating technical drawings (e.g., circuits, floor plans).
   3. Preparing 2D files for laser cutting or routers.
4. Example: A watch design is created with Adobe Software to showcase different variations to clients.

3D Software (For Modeling & Production)

1. Purpose: Creates detailed 3D models that include dimensions, materials, and mechanical properties for production.
2. Examples: Autodesk Fusion 360, Autodesk Inventor, SketchUp, SolidWorks
3. Use Cases:
   1. Designing 3D objects before manufacturing.
   2. Testing material properties using Finite Element Analysis (FEA).
   3. Creating parametric models that can be adjusted easily.
   4. Used with CAM equipment for CNC machining or 3D printing.
4. Example: A bike component is designed in Fusion 360 to ensure it fits perfectly before manufacturing.

Rendering Software (For Realistic Visuals & Advertising)

1. Purpose: Produces high-quality, realistic 3D images for presentations and marketing.
2. Examples: Blender, Maya, 3D Studio Max
3. Use Cases:
   1. Client presentations to showcase how a product will look in real life.
   2. Advertising & promotional materials with photorealistic images.
4. Example: A modern house interior is rendered in Maya to create a visually appealing promotional image.

Surface Modeling vs. Solid Modeling - Simple Explanation

1. When creating CAD models, designers can choose between
   1. Surface modeling and
   2. Solid modeling
2. The choice depends on what they need the model for.

Surface Modeling (For Visual Representation)

1. What it does: Creates a realistic-looking 3D model but only focuses on the external appearance (shape, material, lighting).
2. What it lacks: No internal details, mechanical structure, or data for manufacturing.
3. Examples of Software: Blender, Maya, 3D Studio Max
4. Purpose:
   1. Used to communicate the aesthetic form and scale of a design.
   2. Great for marketing, animations, and presentations.
5. Audience:
   1. Clients who want to see how the product will look.
   2. Designers who need to quickly communicate visual ideas.

Solid Modeling (For Manufacturing & Engineering)

1. What it does: Creates a detailed 3D model that includes exact dimensions, materials, and functional components.
2. What it includes: Internal and external structures, ready for manufacturing.
3. Common File Format: STL (used for 3D printing).
4. Purpose:
   1. Provides precise measurements and functional details for production.
   2. Used for engineering, manufacturing, and CAD/CAM processes.
5. Audience:
   1. Engineers and manufacturers who need production-ready models.
   2. Designers who need technical accuracy for prototyping and fabrication.

To CAD or not to CAD?

Advantages of CAD Software

1. Easy to make changes and improvements
   1. Just like editing a Word document instead of rewriting a whole essay by hand, CAD allows designers to quickly modify designs without starting over.
2. Better teamwork and communication
   1. Similar to how students can collaborate on a Google Doc, CAD enables designers, engineers, and manufacturers to work on the same project remotely and share updates instantly.
3. Safe and secure file storage
   1. Instead of relying on physical blueprints that can be lost or damaged, CAD files are stored digitally. This makes them easy to back up, access, and share when needed.
4. Prevents costly mistakes before manufacturing
   1. Engineers can simulate how a design will function before physically building it. This is like testing a bridge in a video game to see if it will hold weight before constructing it in real life.
5. Reduces waste by minimizing physical prototypes
   1. Traditional manufacturing requires multiple trial-and-error prototypes. With CAD, digital models can be tested first, saving material and costs. This is similar to testing a paper airplane design in a simulator before folding one in real life.
6. Saves time and resources
   1. Since CAD automates many design processes, engineers can work more efficiently. This is like using a calculator for complex math problems instead of solving them manually.
7. Highly accurate designs
   1. CAD ensures precise measurements, reducing human error. This is like using a ruler and grid lines in a design software instead of freehand drawing.

Disadvantages of CAD Software

1. Expensive software
   1. CAD programs often require a large initial investment, much like buying an advanced gaming PC instead of a basic laptop.
2. Specialized training required
   1. Learning CAD can take time and effort, similar to learning how to use Photoshop or a complex video editing program. Not everyone can jump in and start designing without training.

CAD Modeling Strategies: Top-Down, Bottom-Up, or Hybrid?

1. Designers use different strategies when creating CAD models,
2. This depends on the complexity and flexibility required.

Bottom-Up Strategy

1. Features:
   1. Design starts with precise criteria and specifications.
   2. Individual parts are created separately and later assembled into the final product.
   3. No automatic relationships between parts—if one part's dimensions change, other parts must be manually adjusted.
   4. Components can be reused in multiple designs.
2. Use Cases:
   1. Best for designs where parameters are fixed before actual modeling begins.
   2. Suitable for projects with few anticipated changes.
   3. Used for large, complex systems such as buildings, spacecraft, or vehicles.
   4. Common when working with standard parts that are not heavily customized.