AutoCAD is a software application for 2D and 3D computer-aided design (CAD) and drafting – available as a desktop application and as a mobile web and cloud-based app, currently marketed as AutoCAD 360. Developed and marketed by Autodesk, Inc., AutoCAD was first released in December 1982. As Autodesk’s flagship product, by March 1986 AutoCAD had become the most ubiquitous microcomputer design program worldwide, with functions such as “polylines” and “curve fitting”. Prior to the introduction of AutoCAD, most other CAD programs ran on mainframe computers or minicomputers, with each CAD operator working at a graphical terminal or workstation.
AutoCAD was derived from a program begun in 1977 and released in 1979 called Interact CAD, also referred to in early Autodesk documents as MicroCAD, which was written prior to Autodesk’s formation by Autodesk cofounder Mike Riddle. It is used across a range of industries, including architects, project managers and engineers, among other professions. The native file format of AutoCAD is .dwg. This and, to a lesser extent, its interchange file format DXF, have become de facto. Autodesk also market a lower cost version of AutoCAD called AutoCAD LT which lacks certain functionality like 3D Capabilities, Network Licensing, Customization and CAD standards management tools.
Like most of the Autodesk’s softwares, AutoCAD also has a very high retail price of $4,195. They do offer discounted version’s to students and teachers but those versions come with certain type of watermark and cannot be used for commercial purposes. So, let’s have a look at some of the free and open source alternatives to AutoCAD for which you don’t have to spend any money whether you are a student, hobbyist or commercial designing firm.
FreeCAD is a free and open source general purpose 3D CAD modeler. It is aimed directly at mechanical engineering and product design but also fits in a wider range of uses around engineering, such as architecture or other engineering specialities. It is intended to be a feature-based parametric modeler with a modular software architecture, which makes it easy to provide additional functionality without modifying the core system. It is a strong alternative to softwares like SolidWorks and AutoCAD.
As with many modern 3D CAD modelers FreeCAD will have a 2D component in order to extract design detail from the 3D model to create 2D production drawings, but direct 2D drawing or animation is not the focus, although, thanks to its wide adaptability, FreeCAD might become useful in a much broader area than its current focus. It makes use of other open-source libraries from the field of Scientific Computing. Among them are Open CASCADE, Coin3D, the Qt GUI Framework, and Python programming language. Besides FreeCAD’s own file format, it also supports the following file formats: DXF, SVG, STEP, IGES and IFC.
The latest version of FreeCAD is 0.16.
BRL-CAD is a constructive solid geometry (CSG) solid modeling computer-aided design (CAD) system. It includes an interactive geometry editor, ray tracing support for graphics rendering and geometric analysis, computer network distributed framebuffer support, scripting, image-processing and signal-processing tools. Although BRL-CAD can be used for a variety of engineering and graphics applications, the package’s primary purpose continues to be the support of ballistic and electromagnetic analyses.
In keeping with the Unix philosophy, BRL-CAD is basically a collection of libraries, tools, and utilities that work together to create, raytrace, and interrogate geometry and manipulate files and data. In contrast to many other 3D modelling applications, BRL-CAD uses Constructive Solid Geometry rather than Boundary Representation. This means BRL-CAD can “study physical phenomena such as ballistic penetration and thermal, radiative, neutron, and other types of transport”.
The latest version of BRL-CAD is 7.24.2.
QCAD is a computer-aided design (CAD) software application for 2D design and drafting. Released under the GNU General Public License, it is a free and open source software. The QCAD GUI is based on the Qt framework. It is available for Linux, Apple OS X, and Microsoft Windows.
Development on QCAD began in October 1999, starting with code from CAM Expert. QCAD 2, designed to “make QCAD more productive, more user friendly, more flexible and increase its compatibility with other products” began development in May 2002. QCAD 3 was first released in August 2011 with a very complete and powerful ECMAScript interface as major addition. Some of the interface and concepts behind QCAD are similar to those of AutoCAD. It uses the AutoCAD DXF file format internally and to save and import files. AutoCAD DWG support is available as a commercial plugin.
The latest version of QCAD is 3.14.3.
LibreCAD is a free and open source computer-aided design (CAD) application for 2D design. LibreCAD was developed as a fork of QCad Community Edition. The GUI of LibreCAD is based on Qt4 libraries, so it runs on several platforms in the same way.
Most of the interface and handle concepts are analogous to AutoCAD, making it easier to use for users with experience of this type of commercial CAD application. LibreCAD uses the AutoCAD DXF file format internally for import and save files, as well as allowing export to many other file formats.
The latest version of LibreCAD is 2.0.10.
Archimedes is a computer-aided design (CAD) program being developed with direct input from architects and architecture firms. With this design philosophy, the developers hope to create software better suited for architecture than the currently widely used AutoCAD, and other available CAD software.
Archimedes uses its own XML-based open format, which resembles SVG. It does not yet include support for other CAD formats, but DXF support is planned. Some of its CAD features are explode, offset, trimming, filleting, autosave, svg & pdf export and others. It is a free and open source software released under the Eclipse Public License.
The latest version of Archimedes is 0.66.1.
6) Open CASCADE Technology
Open CASCADE Technology (OCCT) is a software development platform. It includes C++ components for 3D surface and solid modeling, visualization, data exchange and rapid application development. Since version 6.7.0 Open CASCADE Technology is available under the LGPL 2.1 making it a free and open source software.
Open CASCADE Technology can be best applied in development of specialized CAD/CAM/CAE applications. The typical applications built with help of OCCT are pre- and post-processors for finite element analysis software, CNC/CMM path generators, numerical simulation programs, etc.
The latest version of Open CASCADE Technology is 7.0.0.
7) CADEMIA Community Edition
CADEMIA is a simple and easy to use modern CAD system with a full functionality for civil engineering and architecture. It is a 2D CAD software with focus on architecture. There are two versions of the software available – CADEMIA professional and CADEMIA community.
CADEMIA was originally designed at the Bauhaus University in Weimar for teaching and research purposes. Following that, further development consistently focussed on making CADEMIA fit for use in CAD-practice. These improvements were undertaken by experts with years of experience in the development of such systems for the building industry. CADEMIA community is a free software which lacks certain functionality as compared to the professional version. However, in future it will be available as version behind the professional edition.
The latest version of CADEMIA Community Edition is 4.0.
8) DraftSight (Bonus)
DraftSight is a freeware 2D computer-aided design (CAD) software application. It lets users create, edit and view .dwg and AutoCAD DXF files. The user interface is quite similar to AutoCAD. The standalone, single-user version of DraftSight is free until a user saves or prints a document for the first time. They will then be asked to activate the product within 30 days using a valid email address and reactivate after six months and thereafter at 12-month intervals.
DraftSight allows users to access DWG/DXF files, regardless of which CAD software was originally used to create them. As stated on its home page, DraftSight uses Teigha Classic for .dwg files and Teigha for .dwg files specifications from the Open Design Alliance to interpret the dwg-file format.
The latest version of DraftSight is 2016 SP1.