Open source software
Here I collected a list of my favorite open source programs. Open source software is software that makes the source code available, next to the software itself. A very popular license for open source software is GNU General Public License (GPL). See for more info GNU GPL website If you don't have that much money too spend or you want to have the liberty to adjust and change the software, then maybe open source software is a good option.

Office software/ office suite

  • Open Office This open source office suite is supported by a large community worldwide and is of very high quality.Check it out to see if it suits your office needs as well.

Internet browsers

  • Firefox This open source browser is developed by the Mozilla foundation and is available in many different languages.If you are looking for an alternative for your current internet browser, check this one out.

Email software

  • Thunderbird Good and fast email program, available in many languages.There are many extensions and addons available for more functionality.

2D graphics / picture editing

  • GIMP for windows Very good image manipulation software, also with many advanced functions.There are many plugins available. The user interface takes some time to get used to..
  • GIMPshop GIMPshop is a modification of the free/open source graphics program GNU Image Manipulation Program (GIMP), intended to replicate the feel of Adobe Photoshop. Its primary purpose is to make users of Photoshop feel comfortable using GIMP.
  • Inkscape Inkscape is a high quality Open Source vector graphics editor.

3D modelling and rendering

  • Blender Blender is a very high quality open source 3D software. It can be used for modelling, editing and rendering 3D models.
  • POV-Ray The Persistence of Vision Raytracer is a high-quality, totally free tool for creating stunning three-dimensional graphics. It is available in official versions for Windows, Mac OS/Mac OS X and i86 Linux. The source code is available for those wanting to do their own ports.
  • K3DSurf K3DSurf is a program to visualize and manipulate Mathematical models in three, four, five and six dimensions. K3DSurf supports Parametric equations and Isosurfaces.

Anti virus

  • ClamAV ClamAV is a open source anti virus scanner. A version for windows can be found at ClamWin

Bittorrent/P2P clients

  • Azureus Azureus is a java-based bittorrent client.
  • Ares Galaxy Ares is a free open source file sharing program that enables users to share any digital file including images, audio, video, software, documents, etc. P2P and bittorrent client

File compression / archiver

  • 7-Zip 7-Zip is a file archiver with a high compression ratio. Handles many different formats such as ZIP ,RAR and 7z.

3D CAD(Computer Aided Design) software

  • BRL-CAD BRL-CAD is a open source CAD software package, originally developed by the US military. Includes solid modelling, rendering and geometric analysis.
  • Open Cascade Open CASCADE Technology is software development platform freely available in open source. It includes components for 3D surface and solid modeling, visualization, data exchange and rapid application development.
  • FreeCAD FreeCAD will be a general purpose 3D CAD modeller. The development will be completely Open Source. As modern 3D CAX modellers it will have a 2D component to extract design drawings from the 3D model, but 2D (like AutoCAD) is not the focus, neither are animation and organic shapes (Maya, 3D StudioMAX, Cinema 4D). FreeCAD will aim directly to mechanical engineering, product design and related features (like CatiaV4 and V5, and SolidWorks). It will be a feature based parametric modeler.
  • Avocado CAD avoCADo :: Open Source 3D CAD

2D CAD

FEM(Finite Element Method) software

  • Code Aster Code-Aster is a large numerical / FEM software project , developed in France. Unfortunately there is little documentation available in English, but it seems to be professional and wellfunded.
  • Impact Impact - a Free Explicit Dynamic Finite Element Program Impact is an open source finite element program suite which can be used to predict most dynamic events such as car crashes or metal sheet punch operations. They usually involve large deformations and high velocities.
  • Elmer Elmer is an open source multiphysical simulation software developed by CSC. Elmer development was started 1995 in collaboration with Finnish Universities, research institutes and industry.
  • gmsh Gmsh is an automatic 3D finite element grid generator with a build-in CAD engine and post-processor. Its design goal is to provide a simple meshing tool for academic problems with parametric input and advanced visualization capabilities.
  • Calculix CalculiX A Free Software Three-Dimensional Structural Finite Element Program

Numerical problem solving

  • Octave GNU Octave is a high-level language, primarily intended for numerical computations.

Open source Rapid Prototyping

  • RepRap RepRap is short for Replicating Rapid-prototyper. It is a self-copying 3D printer .