3D computer graphics (in contrast to 2D computer graphics) are graphics that use a three-dimensional representation of geometric data (often Cartesian) that is stored in the computer for the purposes of performing calculations and rendering 2D images. Such images may be for later display or for real-time viewing.
An example of 3D image:
CINEMA 4D or C4D is a 3-D application that is popular amongst matte painters in film production, largely due to the BodyPaint 3D functionality. It has been used for films such as We Are the Strange, Polar Express, Open Season and Monster House.
Blender is the free open source 3D content creation suite, available for all major operating systems under the GNU General Public License.
LightWave 3D® is a complete modeling, animation and rendering solution.
You can use Google SketchUp to create, modify and share 3D models.