[vtkusers] What is the correct way of updating an actor with changes applied to SetUserTransform?

[Victor Nyberg]

Hi,

First of all I would like to apologise in advance if this question is 
too simple for bothering you with via the mailing list but I have not 
been able to figure it out after quite some investigation.

I have a poly actor which has a vtkBoxWidget that is connected to a 
callback as from the example in the docs:

|def widget_callback(obj, event): t = vtk.vtkTransform() 
obj.GetTransform(t) obj.GetProp3D().SetUserTransform(t) |

All works fine and I am able to move and transform the actor with the 
widget but the transformation is applied to the UserTransform and not 
processed down to the actor properties.

So if I call:

|actor.GetPosition() |

It returns the initial position prior to making the changes with the 
widget. And if I call:

|actor.GetUserTransform().GetPosition() |

I get the updated position relative to the starting point of the first 
interaction.

Do I have to connect it all through a vtkTransformPolyDataFilter and 
then update the input connection to the mapper and also calculate the 
coordinate space offset or is there a simpler way of doing it? ... in short:

*What is the correct way of updating an actor with changes applied to 
SetUserTransform?*

Many thanks in advance.

/Victor

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