Computer-aided design/Computer Aided Drafting

Introduction
Computer Aided Drafting (CAD) means using the computer, instead of the classical tools (pencil, ink, rulers, paper) to create drawings. There are several advantages to this, for example the drawing can be subdivided in smaller parts, that can be reused or be worked on by several architects, updating the drawing is much faster than with hand-made drawings (where you often needed to redraw the whole drawing), and several tools can help you to check your drawing for errors. Besides this, computer generally allows you to work in real-world units, and does the scaling automatically, so your drawing fits on the printer sheet.

CAD Applications are nowadays complex and very carefully conceived. Therefore most of them are highly expensive software. Among the most used worldwide, are Autocad, Archicad, Inventor, Microstation, Vectorworks or Allplan. Almost all engineering and architecture offices on the planet use one of them, so knowing at least some of them is very important in the professional world, and usually the most important requirement on architecture job offerings.

Those applications are generally used to design whole architecture or engineering projects, often from scratch, and to produce the printed drawings that will be used to discuss the project with involved people such as project partners, authorities and clients, and the execution documents that will be used by the building team to actually build the project. Nowadays, all of them can be used to make 2-dimensional drawings directly (similarly to drawing on a sheet of paper), or to build a 3-dimensional model of your project, from which the software will extract 2D drawings that will be printed on paper.

Since CAD applications are focused on technical drawings, additional pieces of software are often used together, for rendering realistic images of the project. Among the most used in architecture are 3DS Max, Maya, Rhino, V-Ray, or Mental ray. Usually, file transfers between CAD software and rendering software is straightforward.

Besides this, several other types of software, not specifically made for architecture, are often used in conjunction with the ones shown above, for example for modeling more organic geometries, or using specific engineering techniques. Among the application that can sometimes be found in architecture offices, are Cinema 4D, Blender, Lightwave, Form Z, Real3D, SketchUp, XSI, SolidWorks or CATIA. Some offices even use them instead of traditional CAD applications.

Finally, it must be noted that the term CAD is an old concept, born when the first computer drawing systems appeared, and people switched from the drawing table to the computer, but continued to work the same way. Today, more and more, big CAD software manufacturers are switching from "drawing-oriented" solution like the software listed above, to a more "full-featured architecture solution", that allows you not only to design your project, but also to manage the enormous quantity of information (such as materials, prices, uses), that goes in an architecture project. There is even a new term for that, called BIM (Building Information Modeling). Advanced BIM software already exist, such as Revit, Archicad and Microstation (last two were CAD software that evolved and can today be called BIM), and a transitional CAD/BIM application based on Autocad called Architectural Desktop.

Most of the above mentioned applications are professional, expensive applications. Some of them offer a learning version for free or at low cost to architecture students. Some have a free version, that has a couple of features less than the full version, such as SketchUp or Solid Edge, and there exist also several free or low-cost solutions, usually very similar (but very limited) to most well-known software like Autocad. Searching for "free CAD application" on the internet should give you many options. There is also a list of free CAD applications at the bottom of this page. In all the software listed above, only Blender is open-source, but still not much used in architecture. There are also a couple of ongoing projects of open-source CAD programs such as FreeCAD but that have until today not reached a level suitable for production work.

Software-specific Courses
This is a list of learning material specially oriented to architecture.

Rhinoceros

 * Features and Overview
 * Learn
 * Grasshopper
 * Grasshopper Tutorials

AutoCAD

 * Introduction to AutoCAD
 * AutoCAD 2D

SketchUp

 * Getting started: General introduction to sketchup
 * Drawing a room: Tutorial showing how to draw a simple room

Blender

 * Official blender tutorials
 * Architecture modeling tutorial: This is a general introduction to modeling architecture with Blender
 * Precision modeling tutorial: This tutorial focuses on modeling architecture with precision
 * Urban design tutorial: This tutorial shows how to use Blender for doing urban design
 * Tree making tutorial: a tutorial oriented at modeling vegetation with Blender and several other open-source tools

FreeCAD

 * Many FreeCAD tutorials including Architecture, Part Design, Product Design, Drafting, 3D Printing, 3D Modeling and more.

Free CAD programs

 * Sketchup (free limited browser-based version, windows, mac osx): http://sketchup.google.com
 * Blender (opensource, windows, linux, mac osx)): http://www.blender.org
 * Solid Edge 2D (free limited version, windows): http://www.solidedge.eu.com/isapi/pagegen.dll/pages?page=free_2d
 * HyCAD (freeware, windows): http://www.drawease.com/index-en.htm
 * LiteCAD (freeware, windows): http://www.litecad.com
 * QCAD (opensource on linux, shareware on windows): http://www.qcad.org
 * FreeCAD (full version free on windows, mac, linux): https://freecadweb.org/