Unlike an artistic drawing, a technical drawing is a tool designed to communicate specific information in a visual, graphic way. Thanks to its universality, the technical drawing can be understood by all parties involved in the product creation process; the engineers, architects, designers, and workers can thus communicate with each other thanks to the drawing. While technical drawings were originally made with ink and paper according to a strictly defined format, it’s now much more common to make them on a computer. In this case, we’re talking about CAD, or computer-aided design. The advantages of CAD are multiple:

  • Visualization of the project in 3D before its creation
  • Ability to quickly make modifications and corrections
  • Easy to exchange data with the various project stakeholders (client, service provider, etc.), and very easy to reproduce and archive the data, since it’s digital

File types

There are three main types of graphic files: vector drawing, raster image, and page description language (or PDL).

In a vector drawing, a line is defined by two points and the text can be modified. The most common vector drawing format is .dxf (for a little history, this format was developed by Autodesk to make the files created by AutoCAD understandable by other software). The most commonly used file formats for 2D plans are .dxf and .dwg (the native AutoCAD format). 3D plans, meanwhile, most often appear in the .stp format.

A raster image, on the other hand, can be compared to a photographic image, and its definition is measured in pixels per centimetre or pixels per inch.

Finally, page description language can provide the most information. The most commonly used page description languages are the PostScript (.ps) format, the Encapsulated PostScript (.eps) format, and the Page Description Format (.pdf).

2D vs. 3D

We should distinguish between computer-aided engineering (CAE) and computer-aided design. A CAE solution lets you virtually model and test the product in three dimensions thanks to digital simulation techniques. CAD, on the other hand, simply allows you to represent the product. 2D CAD programs provide an interface for two-dimensional design. You can use a variety of shapes and tools to construct cutaway and elevation plans. You won’t be able to create drawings or renderings in perspective, however, and you won’t be able to rotate your design or view it from different angles. 3D CAE programs provide an entirely three-dimensional interface. These programs let you design complex objects as 3D shapes, and you can rotate them and zoom in and out.

Technical drawing software

The most common CAD programs for vector drawing are Adobe Illustrator and CorelDRAW. For raster images, the most commonly used programs are Corel PHOTO-PAINT, Adobe Photoshop, and Adobe Fireworks. There are open source alternatives for 2D CAD drawings. The following are the most reliable (it should be noted that these programs work with Windows, Mac, and Linux operating systems):

Only vector images can be read by machine tools: each point and each line in the drawing corresponds to cutting instructions that the machine tool can interpret. At USIMM, we mostly work with the following CAD programs: AutoCAD, Inventor, Geomagic, Solid Edge, and Mastercam.