Google SketchUp 6

Google SketchUp is a deceptively simple, amazingly powerful tool for creating, viewing, and modifying 3D ideas quickly and easily. Google SketchUp was developed to combine the elegance and spontaneity of pencil sketching with the speed and flexibility of today's digital media.

Developed for the conceptual stages of design, this powerful yet easy-to-learn software allows for quick and easy 3D form creation, the result is an interface that supports a dynamic, creative exploration of 3D form, material and light.

Google SketchUp combines a compact yet robust tool-set with an intelligent guidance system that streamlines the 3D drawing process.

Download : http://sketchup.google.com/download.html

Blender 2.45

Blender is the free open source 3D content creation suite, available for all major operating systems under the GNU General Public License.

Author : http://www.blender.org

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IrfanView

IrfanView is a very fast, small, compact and innovative FREEWARE (for non-commercial use) graphic viewer for Windows 9x/ME/NT/2000/XP/2003/Vista.

It is trying to be simple for beginners and powerful for professionals.

IrfanView is trying to create new and/or interesting features in its own way, unlike some other graphic viewers, whose whole "creativity" is based on feature cloning, stealing of ideas and whole dialogs from ACDSee and/or IrfanView! (for example: XnView has been stealing/cloning features and whole dialogs from IrfanView, for 7+ years).

IrfanView was the first Windows graphic viewer WORLDWIDE with Multiple (animated) GIF support.
One of the first graphic viewers WORLDWIDE with Multipage TIF support.
The first graphic viewer WORLDWIDE with Multiple ICO support.

Author : http://www.irfanview.com

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The GIMP 2.4.4

GIMP is an acronym for GNU Image Manipulation Program. It is a freely distributed program for such tasks as photo retouching, image composition and image authoring.

It has many capabilities. It can be used as a simple paint program, an expert quality photo retouching program, an online batch processing system, a mass production image renderer, an image format converter, etc.

GIMP is expandable and extensible. It is designed to be augmented with plug-ins and extensions to do just about anything. The advanced scripting interface allows everything from the simplest task to the most complex image manipulation procedures to be easily scripted.

Author : http://www.gimp.org