CAD Glossary

2D design

Raster vs Vector

Raster Images are made of pixels. Pixels are the smallest pi(x) -cture el -ements that contain colour information. They follow a co-ordinate system and are generally square, sometimes rectangular in shape. They do not scale up without loss of quality. They allow control over individual pixels.

Raster Formats

JPEG/JPG (Joint Photographic Experts Group): JPGs can be compressed with a control on quality and file size. So they are good for web browsers. Generally the standard screen resolution for internet images is 72 ppi. JPGs support the 24-bit colour palette.

GIF (Graphics Interface Format): GIF works well for illustrations and animations. It supports a maximum of 256 colours per frame (8-bit per pixel) selected out of the 24-bit RGB palette. It uses lossless compression.

PNG (Portable Networks Graphic): PNGs support transparency, so they are very useful for non-rectangular looking images. It uses lossless compression just like GIFs.

TIFF (Tagged Image File Format): This format is used to store large sized images that need high quality for print. It contains a lot of meta information, so is good for editing.

Raaster, Pixels and AI AI algorithms start by examining the pixels to identify and extract features from an image. These features could be edges, colors, shapes, or textures.AI uses machine learning models, particularly convolutional neural networks (CNNs), to recognize patterns.Looking at the arrangement and color of pixels, an AI can distinguish between a picture of a cat and a dog, not just by shape but by texture, size, and typical coloration patterns.

Vector Images

Vector images, on the other hand, use mathematical equations (lines and shapes) to represent images. These equations describe points, lines, curves, and polygons which can be filled with colors and patterns. Vector graphics are resolution-independent, meaning they can be scaled to any size without loss of quality. This makes them ideal for logos, text, and other designs that require precision and scalability. Common vector file formats include SVG, EPS, PDF, and AI.

SVG, which stands for Scalable Vector Graphics, is a versatile and widely-used format for vector images. Defined in XML text files, SVG allows for the description of images in a way that can be scaled to any size without losing quality. This makes it particularly suited for graphics on the web, where it can be displayed across devices with different resolutions without degradation.

Conculsion

Raster images are best for detailed and complex images like photographs, where the richness of colors and details matter more than scalability.

Vector images are suited for designs that require scalability and crisp lines, such as logos and typography, where the quality must remain consistent across various sizes and applications.

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