[vtk-developers] vtkCleanPolyData

[Berk Geveci]

> I am more familiar with ITK where the approach to
> backwards-compatibility is that it should always be maintained.
> Changing the type of data returned from a filter is a pretty drastic
> move, even if -- in most cases -- it doesnt break anything obvious.

VTK approach is different. We break backwards compatibility to fix
behavior we believe is wrong. VTK used to assume that all point
coordinates were single precision. To overcome precision issues, many
of the new readers can now provide double precision floats. The right
behavior for a filter is to preserve the precision of its input. This should
have been done for all filters long time ago but we have limited resources.
 Adding a switch to a filter is an ugly, duct-tape solution that will
burden all current and future users. Keep in mind that this will have a
very minor impact on compatibility as most "legacy" codes that use VTK
will produce single precision points.

-berk