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Laser CNC Engraving and Cutting + EdLaser

3. CAD CAM Overview

3.1. Vectors Vs Bitmaps

There are two ways to store graphics data:

  1. Vector: "vector graphics" - shapes are stored as mathematical code- infinitely scalable without resolution issues - small efficient code/files- formats are "SVG" and "DXF" etc.
  2. Bitmaps: older method of storing images/text- grid of pixels (dots) for which the colour is stored fore each pixel- inefficient and large files for relatively small images and resolution decreases as image is expanded- examples are JPG, BMP & PNG

Normal CAD-CAM and CNC machines work with vector graphics where the CNC machine "follows" the mathematically defined lines and cannot work with "pictures" or bitmaps.  Special software or techniques are needed to get CNC machines to engrave bitmap images.  

It is extremely important to understand the difference and what file type you have because the technique used depends on being either "Vectors" or "Bitmaps".

"Raster Engraving" is a technique that processes bitmap images, pixel by pixel and allows the image to be engraved.  Raster Engraving takes is very slow because it sweeps the image at a fraction of a millimeter per pass and fires the laser whenever a "dot" is required.