> I'm guessing a "range scanner" is a device that determines the distance
> to the surface of an object from a certain point or points, allowing it
> to get points on the surface of the object...sort of like real-world
> raytracing. The range image is like a depth buffer from a camera that
> wraps around the scene.

The range scanners I am familiar with use a laser to determine distance.
The basic concept can be constructed using a simple range finder (I believe
hunters use these) mounted on a 2 axis mount.  The more expensive versions
are automated and more precise, they are capable of collecting millions of
points in minutes.  The resulting data is like having a sphere with a grid
on it - each grid cell has a range.  Now you have spherical coordinates for
all points seen by the scanner - easily converted to rectangular coordinates
and aligned with other scans.  The data for each cell can include intensity
(even for seperate channels of RGB for color!)

The data collected is like have a completly dark scene with a single point
light (no radiosity please :-).  The areas that are *lit* are the areas that
will be scanned up to the range limit and object reflectivity requirements
of the of the scanner.

> It looks like these files are provided for people doing research in
> surface reconstruction algorithms who don't have access to a scanner. In
> other words, these are not models, but raw data to be used to generate
> models. They would be fairly useless for POV.

You are right - just points have limited use directly in POV, but the number
of things that can be done with the points is limitless.  Most don't require
special knowledge, just creativity:

Using spheres for each of the points one can re-create the scene.  By
controling the size of the spheres the *looks* of the scene can be easily
adjusted.  This method can produce from fairly decent images.  If available,
intensity or color could be added to each shpere giving a better image.

The data could be used to generate a height field for terrain generation
(I've done this with an entire open pit coal mine).

A mesh can be created from the points giving an actual surface.

This is just a small spattering of what I have managed to do with point
clouds and POV.

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