[vtkusers] speed

[Sathya Krishnamurthy]

Hello Everybody

Loading a huge mesh was not a problem for us. We had problems doing
extract geometry on the data. That took most of the CPU time even during
run-time. We used a custom binary data reader.

> Of course as Will Schroeder pointed out ascii reading is slow, and if you
> try to make tcl calls for each data you're dead.
> 
> But I also found that a lot of time is spent in the UnstructuredGridReader,
> after the loading, to compute the mesh skin to display it.
> I couldn't find how to swith off this computation, e.g. to display only the
> bounding box. 
> 

cheers
~sathya