[vtkusers] PolyData Translation Problem

[David Gobbi]

The renderer automatically resets the camera on the first render,
it resets both the field-of-view and the position.  That is why it
"seems" like the position and scale are being ignored.  But they
are not being ignored.  It is just that the renderer is automatically
resetting the camera, and this causes the camera to move to the
new actor location.

The easiest way to avoid this is to render once (with the original
position), then apply the UserTransform to the actor (or the
vtkTransformPolyData), and then render again.  The camera
reset will only occur on the first render.

 - David


On Thu, Oct 27, 2011 at 10:32 AM, Wenlong Wang <scc.wwl at gmail.com> wrote:
> Hi, Jothybasu,
>
> Thank you very much for your reply.
>
> No, I didn't use it in my app. Does that matter? If so, why the scale and
> rotate functions works without vtkTransformFilter?
>
> Wenlong
>
> 2011/10/27 Jothybasu Selvaraj <jothybasu at gmail.com>
>>
>> Are you using vtkPolyDataTransformFilter along with vtkTransform?
>>
>> Jothy
>>
>> On Thu, Oct 27, 2011 at 5:13 PM, Wenlong Wang <scc.wwl at gmail.com> wrote:
>>>
>>> Hi everyone,
>>>
>>> I'm trying to scale, rotate and translate my polydata. My strategy is
>>> using vtkTransform to do these operations one by one. The order is scale,
>>> rotate and translate. I calculate the transform parameters and use
>>> vtkTransform::Scale, ::RotateZ() and ::Translate() to define the
>>> transformation. Then I pass this transformation to my camera by
>>> vtkCamera::SetUserTransform(). After that, I do the visualization pipeline
>>> again to show the new polydata object. And the visualization pipeline is
>>> capsualted as an independent function.
>>>
>>> So far, the scale and rotate works well and the polydata changes as I
>>> expected. However, as I start to translate it, it disappears! It doesn't
>>> work even I put simple numbers as the input parameters.
>>>
>>> I tried to pass the transform to my actor and use
>>> vtkActor::SetUserTransform to do it. But again, the scale and rotate works
>>> well and translate failed.
>>>
>>> Can anyone give me some advice? I'll be extremely appreciate it!
>>>
>>> Thank you very much!
>>>
>>> Best wishes
>>> Long