Where can I get Rapid?
It appears to be RapidForm which has now been bought out (or changed name possibly) to 3D Systems Geomagic.  The website is here.  I found this by looking for mesh refinement software matching the term Rapid and that seemed likely the best match.  In particular, it appears to be GeoMagic XOS.  I don't personally have any experience with the particular software.

Basically the point behind the software is to make refined meshes from a point cloud.  3D scanners like the Kinect don't actually form a mathematical model, instead, they generated large numbers of points at a given distance from the sensor.  These points are formed into a cloud which then has to be modeled into a vector based solid mesh for rendering purposes.

This process is actually incredibly similar to converting a bitmap image into a vector graphic, but it has to be done to produce smooth, solid surfaces in 3d, so it's a bit of a complex and specialized operation.  Software like this allows for the best fit mesh to be found and to ensure that it makes a solid, detailed mesh that doesn't have holes in it that could cause problems with the geometry.