You can use Google SketchUp to create, modify and share 3D models.

Google SketchUp Pro 7 is a suite of powerful features and applications for streamlining your professional 3D workflow.

SketchUp Pro 7: Create, modify and share 3D models

All the intuitive modeling, visualization and collaboration features of SketchUp 7, plus exporters for a long list of 2D and 3D vector file formats. Also, generate tabular reports based on the entities in your models.

LayOut 2: Create flexible 2D presentations, quickly

Link your models to multi-page 2D presentation documents, add images, text and graphics, and share your designs as high-resolution prints, digital exports and onscreen slide shows.

Dynamic Components: Make smarter models with custom behaviors and attributes

Teach components to animate and scale like they do in real life. Add custom attributes that extend your models' usefulness. Build configurable components that are easy for everyone to use.