[vtkusers] edges between moving assemblies

[Sebastien Jourdain]

Hi Clement,

So if only the camera is moving, you don't need to dynamically update
the coordinates of the tip of your tube/line ?
But it's true that you will have to setup absolute coordinates for the
tips of your tube/line.
Depending on the way you build your sphere, you should be able to
easily compute them.
Either by getting the Center from the source or the Position of the
Actor or combining both...

Hope that helped,

Seb


On Thu, Nov 4, 2010 at 11:12 AM, creusot <creusot at cs.york.ac.uk> wrote:
> Hi Seb,
> The idea is to visualize correspondences (lines) between landmarks (small
> sphere) on two static 3D objects.
> The assemblies content is fixed. I just use the
> vtkInteractorStyleTrackballActor functionality to move the two assemblies
> relative to each other and get the best view of the correspondences.
> I was hoping there is a way to define position relatively to object rather
> than by absolute coordinates. It would be very handy to have different
> frames of reference, the absolute one and others attached to objects.
> If it is not possible, can you advise me a good example of code using
> observer updating a polydata?
>
> On a different matter I have notice that mouse event observer doesnt seem to
> work with vtkInteractorStyleSwitch but works with
> vtkInteractorStyleTrackballCamera.
>
> Example of code(python)  that doesnt work (the function handle_mouse is
> never called):
> style = vtk.vtkInteractorStyleSwitch()
> style.SetCurrentStyleToTrackballCamera()
> style.AddObserver("LeftButtonPressEvent", handle_mouse);
>
> Example that works:
> style = vtk.vtkInteractorStyleTrackballCamera();
> style.AddObserver("LeftButtonPressEvent", handle_mouse);
>
> Is this a bug or a feature?
>
> Thanks for your help,
> Best regards,
> Clement.
>
> On 04/11/10 14:32, Sebastien Jourdain wrote:
>>
>> Hi Clement,
>>
>> I guess you will have to use Observer to listen change event on the
>> sphere and update the tube/line start/endpoint according to the new
>> coordinates.
>> Do you change the assembly location, or the dataset itself ?
>>
>> Seb
>>
>> On Wed, Nov 3, 2010 at 12:11 PM, creusot<creusot at cs.york.ac.uk>  wrote:
>>
>>>
>>> Hi,
>>> I have a small problem to design the scene I want with VTK.
>>> Basically I would like to have two Assemblies composed of several Actors
>>> (small spheres) and a set of edges between the two Assemblies connecting
>>> a
>>> subset of those spheres.
>>> Creating the Assemblies is very easy but I don't know what to do for the
>>> edges.
>>> If I create an edge as an Actor using the initial position of the sphere
>>> then the edges doesnt move when I move one of the Assembly compare to the
>>> other.
>>> How can I create a line or a tube which extremities are from two
>>> different
>>> objects and are not fixed?
>>> Best regards,
>>> Clement.
>>>
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