[vtkusers] picking problems/getting Point IDs

[Malcolm Drummond]

Hi Karin

For every input point, the entire source geometry (points and cells) is
transformed and copied to the glyph filter output - so it's quite common to
get large datasets from glyphing (especially with spheres). So the
point/cell id you're getting back is probably correct.

Getting the "original" ids back isn't too difficult. If you're not adjusting
the source while you build the glyphs you can just integer-divide by the
number of cells/points of the source dataset (depending on whether you use
cell/point picking). If you use a programmable glyph filter you can build a
lookup table to get glyph-id (ie input-point-id) from pick-id. Clear the
lookup-table in the StartMethod and add the lookup-table entries during the
GlyphMethod. The lookup-table means you can recover input ids even if you
messed with source-types and resolutions while building the glyphs.

Malcolm

----- Original Message -----
From: Karin Faulhaber <faulhabe at ipf.uni-karlsruhe.de>
To: VTK users list <vtkusers at public.kitware.com>
Sent: Wednesday, April 04, 2001 6:51 PM
Subject: [vtkusers] picking problems/getting Point IDs


> Hi,
>
> I still have a problem getting the IDs of picked points:
> I have a vtkPolyData with a couple of points building one polyVertex. If
> I pick one of them, I get the right ID. OK.
>
> Next step: These points have scalar values attached which I use for
> Glyphs (spheres for the moment). If I pick now, I seem to get some ID of
> the sphere or something. Anyway, I only have 4 points in this test
> dataset, and the IDs I get are something like 132.
> Using a cellPicker instead of a pointPicker doesn't help, and since a
> vtkGlyph isn't a vtkProp I can't change it to not pickable.
>
> So, does anyone have an idea how to get the point ID in a polyvertex
> when there are glyphs at the pick location???
>
> Thanks!!!
> Karin
>
>
>
>
> --
> Karin Faulhaber
> Universitaet Karlsruhe
> Institut fuer Photogrammetrie und Fernerkundung (IPF)
> Englerstr. 7
> 76128 Karlsruhe
>
> Tel: 0721/608-3676
> E-Mail: faulhaber at ipf.uni-karlsruhe.de
>
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