[vtkusers] Adding new file formats into VTK

[tom fogal]

Currently our group has external utilities which convert from the file format
our models output into VTK's format. Particularly for large datasets, this
causes a great inefficiency, as the data must be read from the disk, 
reformatted in memory, and written back to the disk... and then read back
from disk when VTK loads it.

We are interested in extending VTK to recognize the file format we are using
to alleviate this excess bottleneck. I was hoping to get some advice on where
to start and some sort of vague time estimate from someone who has done this
sort of thing before.

It looks as if we would want a new object derived from a 'vtkDataSetSource'
which implements a number of functions (*New, vtkTypeRevisionMacro,
PrintSelf, Update, ExecuteInformation, etc...). Am I on the right track?
Is there documentation anywhere which explains the member functions that
would need to be implemented? Is there a particularly 'good'/simple file
reader that we might want to model our code around?

Thanks,

-tom