Week 02: Computer-aided Design
2D and 3D Design
This week, Sophia and Kenny introduced us to the fundamentals of 2D and 3D design. As someone without a design background, this week helped me understand the basic logic behind how images and models are constructed.
Before learning specific software tools, I first needed to understand an important concept: the difference between bitmap (raster) images and vector graphics.
Understanding Bitmap and Vector Graphics
What is a Bitmap (Raster) Image?
A bitmap image is made of tiny squares called pixels. Each pixel stores a specific color value. For example, a 1200 × 800 image contains 960,000 pixels, and the computer stores the color information for every single one of them.
When we zoom in on a bitmap image, the pixels become larger, and the image starts to look blurry or jagged. This is because the number of pixels does not increase, they simply get stretched.
Common bitmap formats include: JPG / JPEG, PNG, GIF, BMP, TIFF.
Bitmap images are ideal for Photographs, Scanned images, Complex color gradients, Textures, etc.
They are excellent for storing detailed color information but are not suitable for scaling up.
What is a Vector Image?
A vector image is completely different. Instead of storing pixels, it stores mathematical descriptions of shapes, such as: Points, Lines, Curves, Polygons.
For example, instead of storing thousands of pixels to describe a circle, a vector file simply stores the mathematical formula of a circle (center position and radius).
When we scale a vector image up or down, the computer recalculates the formula, so the image always remains sharp and clear.
Common vector formats include: SVG, EPS, PDF, AI
Vector graphics are ideal for: Logos, Icons, Posters, Technical drawings, Laser cutting files, CNC paths, PCB outlines.
For digital fabrication, vector files are essential because machines follow paths, not pixels.
GIMP and Inkscape
After understanding the theory, I explored two open-source tools: GIMP and Inkscape.
GIMP (GNU Image Manipulation Program) is a raster (bitmap) image editor, similar to Photoshop. It works directly with pixels.
It is suitable for Photo editing, Cropping and resizing, Color correction, Removing backgrounds, Cleaning scanned images. Its native format is XCF, which preserves layers, but it can export to formats like PNG and JPG. GIMP is mainly used when working with photographs or pixel-based images.
I took a photo of the grapefruit, looks a bit dark, and I changed the color saturation has been increased by 10.
Inkscape
Inkscape is a vector graphics editor, similar to Adobe Illustrator. It works primarily with SVG files and allows editing of: Paths, Nodes, Strokes, Fills, Text.
Inkscape is commonly used to Create logos and icons, Design posters, Prepare files for laser cutting or vinyl cutting, Precisely control dimensions in millimeters. For fabrication workflows, Inkscape is very important because machines require clean vector paths.
Typical Workflow
A common workflow combining both tools could be:
Clean or adjust a bitmap image in GIMP (e.g., remove background, improve contrast).
Export it as PNG.
Import the image into Inkscape.
Use “Trace Bitmap” to convert it into vector paths.
Adjust nodes and paths.
Export as SVG or DXF for fabrication.
This helped me understand how bitmap and vector tools complement each other.
Practical Exploration This Week
This week, I downloaded Inkscape (Windows version) and started practicing basic operations.
I learned how to:
Adjust the page size (Ctrl + Shift + D)
Set the document size to 30 cm × 30 cm
Draw basic shapes like circles
Use path tools
Experiment with curve drawing
I wanted to decorate a Chinese character “Fu” (福) with some ornamental curves. I found that Inkscape is much more precise than PowerPoint for this kind of design because I can directly control paths and nodes.
What is a Bézier Curve?
While learning Inkscape, I encountered the concept of Bézier curves.
A Bézier curve is a mathematically defined curve controlled by points and handles. When using the curve tool in Inkscape, each segment is created using: A start point, An end point, Control handles, By moving the control handles, the shape of the curve changes smoothly.
Almost all vector graphics, fonts, and SVG shapes are built using Bézier curves. Understanding this concept helped me realize that vector graphics are based on mathematical logic rather than pixels.
Introduction to 3D Design Concepts
In addition to 2D design, we were also introduced to basic 3D modeling concepts.
CSG (Constructive Solid Geometry)
CSG is a modeling method, not a specific software. It builds complex shapes by combining simple primitives such as: Cubes, Cylinders, Spheres.
Using Boolean operations: Union (add), Difference (subtract), Intersection
For example, subtracting a cylinder from a cube creates a cube with a hole.
CSG logic is especially useful for mechanical parts, enclosures, and 3D printing components.
Blender
Blender is a free and open-source 3D creation software. It can be used for Modeling, Rendering, Animation, Visual effects
Blender supports multiple modeling approaches, including polygon modeling and Boolean operations. Compared to engineering-focused CAD tools, Blender is more oriented toward visual and artistic creation.
Reflection
This week was foundational for me. Before this class, I used tools like Canva and PowerPoint for visual design without understanding the underlying logic.
Now I understand:
The difference between bitmap and vector graphics, Why vector files are necessary for digital fabrication. How GIMP and Inkscape serve different purposes, How Bézier curves define vector shapes, The basic logic behind 3D modeling using CSG
Although I am still a beginner, this week helped me build a structured understanding of both 2D and 3D design fundamentals.