[vtkusers] PolyData Translation Problem

[Wenlong Wang]

Hi David,

Thank you for your advice.

In my app, the scale and rotate is not ignored, they works. For translation,
I don't know, after I applied translation, the actor disappeared from my
screen. And the transform is not passed to actor but camera. For rendering,
I totally agree with you, I render the render window first time to show my
actor, then I apply all the transformation. At last, I render again to show
the changed actor.

Wenlong



2011/10/27 David Gobbi <david.gobbi at gmail.com>

> 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
>
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