[vtkusers] vtkPropAssembly with vtkInteractorStyleTrackballActor behaviour

[Bill Lorensen]

Dean,

That's great that the cast works. As you noted, since the labels are
2D actors. they can't be easily moved.

Bill

On Mon, Feb 22, 2010 at 5:25 PM, Dean Inglis <dean.inglis at camris.ca> wrote:
> David, Bill,
>
> Ive looked into vtkAxesActor and wanted to point out a
> few things.
>
> - vtkAxesActor is a hybrid object with 2D and 3D actors
> and currently only returns the 3D actors in the prop collection, but those
> actors could
> be cast to vtkProp3D's, added to a vtkAssembly and then moved by the
> interactorstyle:
>
>  vtkSmartPointer<vtkAxesActor> axes = vtkSmartPointer<vtkAxesActor>::New();
>   vtkSmartPointer<vtkPropCollection> collection =
> vtkSmartPointer<vtkPropCollection>::New();
>  axes->GetActors(collection);
>  collection->InitTraversal();
>  vtkSmartPointer<vtkAssembly> movableAxes =
> vtkSmartPointer<vtkAssembly>::New();
>
>  for(unsigned int i = 0; i < collection->GetNumberOfItems(); i++)
>   {
>   movableAxes->AddPart((vtkProp3D*)collection->GetNextProp());
>   }
>
>  renderer->AddActor(movableAxes);
>
>
> - I tried to get picking to work properly in the case of
> vtkInteractorStyleTrackballActor
> by copying much of the path code from vtkAssembly: it works, but I couldnt
> figure out how to move the labels (in a reasonable amount of time).
> vtkAxesActor was originally
> intended for use with vtkOrientationMarkerWidget and at the time it was
> added to vtk
> I wasnt thinking of the scenario you presented in the MovableAxes example.
>
> Dean
>
>
>
> There is a bug (or feature) in vtkAxesActor.
>
> GetActors returns a PropCollection, NOT a Prop3DCollection. The style
> requires that the picked prop a a Prop3D, not a Prop.
>
> It gets worse. The AxesActor is actually composed of Actors and
> Actor2D's (the text is 2D). So even if we fixed AxesActor, the labels
> won't rotate. I suspect that is why GetActors returns a
> PropCollection.
>
> Also, we can't fix AvesActor without breaking backward compatibility
> unless we add a new method, something like GetProp3Ds().
>
> Bill
>
> On Sun, Feb 21, 2010 at 11:30 AM, David Doria <daviddoria+vtk at gmail.com>
> wrote:
>>
>> On Sun, Feb 21, 2010 at 11:01 AM, Bill Lorensen <bill.lorensen at
>> gmail.com>
>> wrote:
>>>
>>> Can you provide a small example that illustrates the problem?
>>
>> Sure:
>> http://www.vtk.org/Wiki/VTK/Examples/MovableAxes
>> You'll notice that you can interact with the cone, but not the axes.
>> Thanks,
>>
>> David
>> _______________________________________________
>
>