SketchyPhysics, the plugin for Google SketchUp, was implemented entirely by Chris Phillips in his free time. Neither Google, nor the group that made the physics engine was involved. It was an admirable effort, and we applaud Chris for giving such a powerful plugin out for free!
This Wiki is being constructed by fans of SP, to help new users and show old ones some new tricks. Chris doesn't have the time to create documentation, so it's been somewhat lacking in the past; this is hopefully the answer.
SketchyPhysics was written in Ruby script, using the Newton Dynamics engine to control the movement of objects in the model with physics. While the engine is used, not all features have been added; this means that SP is constantly being improved, with each passing release adding something new.
SPIV will be quite special, because it will be totally re-written from the ground up. Because of small errors in the creation of the original, it is impossible to copy joints properly, and joints must be laboriously connected with the JCT. SPIV will change all that! It will also add a number of new features, which are currently being tested and discussed.