[vtkusers] Re: Multiple actors with same image

[Roger Blum]

Hi David,

Thanks for showing me an efficient way to do this.
I 've also tried vtkGlyph3D, which is exactly what
I need.

Now of course I have more questions:
- Is it possible to only zoom the background?
  I have a geographic map as background and
  put some objects (at the moment cubes) with
  the vtkGlyph3D on it.
  If I see the whole map, I cannot see my objects.
  I would like to have them fixed in size, so I can see
  them at every zoom level.
- How can I give my cubes (generated with the
   vtkCubeSource) a color?
- Can every cube have it's own direction (at the
   moment (all cubes have the same)?
- How can I select / pick one of those cubes?
- If I move the mouse over the scene I would like
   to know the current position (world coords).
   How can I get those?

Thanks again for your (and of course any other) help,
Roger

"David Gobbi" <dgobbi at atamai.com> schrieb im Newsbeitrag 
news:20050824063056.31833.qmail at web88005.mail.re2.yahoo.com...
Hi Roger,

To do this efficiently, you'll have to use the same
texture for all of the actors.  So forget about
using vtkImageActor or vtkImageMapper, you need to
go one level deeper.

Create a vtkTexture and set its input to your image.
Then use vtkPlaneSource to make a rectangular polydata
that the texture will stick to.

Use the texture and the polydata to create as many
actors as you need.

You should also take a look at vtkGlyph3D.  If you
use glyphs to make the entire collection of little
planes into a single actor, then performance will
skyrocket as compared to having a separate actor
for each little plane.

 - David



--- Roger Blum <roger_blum at swissonline.ch> wrote:

> Hello,
>
> I would like to display hundreds of image actors
> (bitmaps / symbols) in a 3D
> scene with Tcl/Tk.
> Every actor has it's own position, but all have the
> same symbol. It should
> be possible to select/interact with each actor.
>
> What kind of data source do I choose (vtkPoints,
> vtkPointsSource,
> vtkBMPReader, ..)?
> Which filters do I have to apply ?
> Do I have to create a vtkImageMapper, and what kind
> of actor do I use then?
> Or can I simply use the vtkImageActor?
>
> I 'm experimenting with vtkGUI 1.0 which is great
> for this purpose.
>
> Thanks in advance for your help!
>
> Roger
>
>
>
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