SketchUp,
currently in beta stage, is an application that allows you to create your own 3D
objects, color and texture your designs, use real-time shadowing effects and
grab from a large library of pre-configured objects to add to your design. And
as is always the case with most of Google's software, it is completely free.
There is also a commercial version called
SketchUp
Pro 5 which has a host of additional features, but you may want to take a
stab at the free version first to see if it's suitable for your needs.
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