Download Google Sketchup
You can download Google Sketchup directly from the Sketchup download page.
It is free and downloads in minutes. The pro version Google Sketchup Pro 7 costs $495 and can be downloaded from the same page.
Below we tell you a little more about Sketchup – the free version – and some other free 3D software you may be interestedin. Google Sketchup is very powerful but like all software, it has its limitations; that is when programs like Blender or Artof Illusion step up to the plate. The most attractive feature of Sketchup is how easy it is to learn for beginners; ease-of-usewas built in from the start to encourage design amateurs to download it and create 3D buildings for Google Earth. However, the potentialof this program goes far beyond that. You can see some examples of that in the Google 3D Warehouse.
Google Sketchup 
Drawing in 3D became a whole lot easier when Google acquired Sketchup and improved it – primarily to encourage people to model 3D buildings for Google Earth (which turned out to be a smart move: a large workforce working for free while having fun placing detailed architecture all over Google Earth).
SketchUp is 3D can be used by everyone, from a beginner to advanced level.Once you download Google SketchUp you can immediately begin to create, refine and share 3D models. It is the easiest of all 3D modeling programs to learn, which is why it became hugely popular since its release in 2005. SketchUp’s reduced toolset, guided drawing system and tidy look-and-feel were designed to keep your mind free to concentrate on getting your model built as efficiently as possible, and having lots of fun while doing it.
Other 3D programs:
Blender
Blender 3D is another 3D modeling, animation and rendering tool for all platforms. Blender’s interface is among the best, its rendering is very fast and its modeling and realtime 3D tools are intuitive yet very powerful. A testimony to how well it performs is the sheer size of its enthusiastic user community. It has been described as a revolutionary creativity tool and has won many awards.Blender is a free open source 3D content creation suite, available for all major operating systems under the GNU General Public License.
Software4free: Highly recommended!
Art of Illusion
Art of Illusion is also a free download, opensource 3D modelling and rendering studio. Remarkably, it is written entirely in Java, and should be usable on any modernJava Virtual Machine. The current version is stable and powerful enough to be used for serious, high end animation work.Many of its capabilities rival those found in commercial programs. Some of the highlights include subdivision surface based modelling tools, skeleton based animation, and a graphical language for designing procedural textures and materials.
Persistence of Vision
POV-Ray ThePersistence of Vision Ray tracer is a high-quality, totally free tool for creating stunning three-dimensional graphics.
POV-Ray works takes a totally different approach to programs like Google Sketchup and Blender.
The Persistence of Vision Ray-Tracer creates three-dimensional, photo-realistic images using a rendering technique called ray-tracing. It reads in a text file containing information describing the objects and lighting in a scene and generates an image of that scene from the view point of a camera also described in the text file. Ray-tracing is not a fast process by any means, but it produces very high quality images with realistic reflections, shading, perspective and other effects.
3DCanvas
3D Canvas from Amabilis is a freeware real-time 3D modeling and animation tool that incorporates an intuitive drag-and-drop approach to 3D modeling. It has a large user community and excellent documentation. It is possible to upgrade from the free version to professional versions, 3D Canvas Pro and Plus. Download from amabilis.com.
Gallery Wings 3D
Gallery Wings 3D Wings 3D is an open-source polygon mesh modeller with an user interface that is easy to use for both beginners and advanced users. You can create good models from scratch or work with imported ones. The program is stable and well documented, has a simple straight-forward interface and a fast workflow.
Anim8or
Anim8or is a 3D modeling and character animation program. Like Wings3D, it is still in development but both have a loyal following and a large number of capable developers working on it.
DAZ | Studio
DAZ | Studio Free 3D posing and animation software.
DAZ|Studio allows you to easily create beautiful digital art. You can use this software to load in people, animals, vehicles, buildings, props, and accessories to create digital scenes. DAZ|Studio includes two pre-configured scenes ready to “Load & Render” within DAZ|Studio. Double-click on the scene thumbnails inside of DAZ|Studio, and everything will come on screen posed, lit, and ready to create a stunning digital image.