[vtkusers] Re: Multiple actors with same image

[David Gobbi]

Hi Roger,

To zoom the glyphs, you need to add an observer to the
Renderer's RenderEvent, and each time your observer
is called, you need to check the renderer's camera,
figure out how big your glyphs need to be in order for
them to be visible, and adjust the cube size accordingly.

I'm fairly sure that you can set the orientations of the
individual glyphs, but I have no experience in actually
doing this.  Look through the docs and the examples
and I'm sure something will pop up.

I'll leave the other questions for someone with more
experience in using glyphs.

 - David


Roger Blum wrote:

>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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>>
>
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