Sketchup is sketch-based 3D modeling program for the conceptual phases of design. With it's easy inteference One can create own 3D model easily and smoothly.
Sketchup is also very useful for creating 3D animation. SU Animate is an animation plug-in for Google SketchUp 6, 7 or 7.1. It creates creates animations inside SketchUp 6 or 7 Windows and the animation can be exported as video animation files or as series of image file (in the form of an Audio Video Interleave or AVI on Microsoft Windows and QuickTime on Mac OS X)
There are lots of website which offer free download for animation plugins. I am suggesting some websites and the links are given below for the help of users.
http://www.sketchupdownload.com/
http://www.sketchup4architect.com/
