[vtkusers] Is there any way to preserve some of the originalpoints thru decimation?

[Chris Zakrewsky]

Dear Mathieu,

I am trying to determine whether VTK has such capability exposed
in API somewhere, because internally, as you stated, it is already used
for processing boundary vertices.

>What do you call a subset ? Any kind or a particular one?

Example: think a digital terrain model where some polygons
represent road constructions. The whole data set has to be
simplified by decimation, yet none of vertices defining any of
dykes and viaducts should be moved (that assumes that
they were tagged prior to processing).

>User interaction ?

Either user interaction or tagging affected vertices in some way,
or both.

Thanks a lot for your time, it is really, really appreciated.

Very best regards,
/Chris Zakrewsky


>From: Mathieu Malaterre <mathieu.malaterre at kitware.com>
>
>	No I don't think there is such options in vtkDecimate* class. What do you 
>call a subset ? Any kind or a particular one? Such as boundary vertex ? If 
>so then yes you can 'freeze' the boundary vertex 
>(BoundaryVertexDeletionOff).
>
>	Otherwise you'll have to look at the code to implement such enhancement. 
>How do you plan to pass such arbitrary points ? User interaction ?
(...)
>Chris Zakrewsky wrote:
(...)
>>     Is there any way to preserve some arbitrary subset of vertices
>>     (from a mesh) unchanged thru the decimation process? (i.e.     freeze 
>>some vertices, while the rest can be decimated by     vtkDecimate or 
>>alike)
>>
>>Is this capability available in VTK at all?
(...)

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