[vtkusers] Open source 3D medical imaging reconstruction software

[Tatiana Al-Chueyr]

(answer bellow)

> Why did you choose the GNU GPL 2 license? As you know, the VTK
> BSD-style license more open.
>
> Bill

We've chosen GNU GPL 2 because we find important that people who
improve InVesalius and distribute it, also make improvements available
to the community. We believe that, this way, we'll have more
contributors and a better software.

Some years ago, when we didn't use GPL, we had a serious problem
regarding ownership. As InVesalius is only sponsored by the Brazilian
governement (until now, at least), this was a way to "protect" the
project's freedom -- using a viral license that "forces" distribution
of the changed (and distributed) source-code.

Considering BSD-style license, I find it adequate to VTK, as - as far
as I know - there are companies who invest on VTK's development and
want to make proprietary software using it.