# Actor flash once after change actor input connect

**URL:** https://discourse.vtk.org/t/actor-flash-once-after-change-actor-input-connect/5642
**Category:** Support
**Created:** [April 26, 2021, 1:06pm UTC](https://discourse.vtk.org/t/actor-flash-once-after-change-actor-input-connect/5642 "2021-04-26T13:06:28Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![11112](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/1/d78d45/32.png) [@11112](https://discourse.vtk.org/u/11112)
#### Post date: [April 26, 2021, 1:06pm UTC](https://discourse.vtk.org/t/actor-flash-once-after-change-actor-input-connect/5642/1 "2021-04-26T13:06:28Z")

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I have an actor in renderer window with QVTKOpenGLNativeWidget  
And every time I changed actor input poly data, than I interact with mouse.  
It will show old vision suddenly.  
Why that happened? Any solution?

```auto
actor->GetMapper()->SetInputPort(newPolyData);
renderer->Render();

```

That’s all

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### Author: ![mwestphal](https://discourse.vtk.org/user_avatar/discourse.vtk.org/mwestphal/32/19_2.png) [@mwestphal](https://discourse.vtk.org/u/mwestphal)
#### Post date: [April 26, 2021, 2:06pm UTC](https://discourse.vtk.org/t/actor-flash-once-after-change-actor-input-connect/5642/2 "2021-04-26T14:06:53Z")

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@Thomas_Caissard : Did you hit this issue recently ?

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### Author: ![Thomas\_Caissard](https://discourse.vtk.org/user_avatar/discourse.vtk.org/thomas_caissard/32/2636_2.png) [@Thomas\_Caissard](https://discourse.vtk.org/u/Thomas_Caissard)
#### Post date: [April 26, 2021, 3:30pm UTC](https://discourse.vtk.org/t/actor-flash-once-after-change-actor-input-connect/5642/3 "2021-04-26T15:30:20Z")

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Did you correctly attached the renderer to the window and the window to the renderer ? What most likely happens is that your window is not aware of the renderer, and when you interact with it, it renders an empty one.

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### Author: ![11112](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/1/d78d45/32.png) [@11112](https://discourse.vtk.org/u/11112)
#### Post date: [May 10, 2021, 2:43am UTC](https://discourse.vtk.org/t/actor-flash-once-after-change-actor-input-connect/5642/4 "2021-05-10T02:43:25Z")

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Yes, I did assign renderer to window and widget.  
Here is a demo image.  
 ![ezgif-1-826e11a35d84](https://discourse.vtk.org/uploads/default/original/2X/a/ae0c0b157f42af290953544d76926ba7bbae6cfd.gif)

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### Author: ![11112](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/1/d78d45/32.png) [@11112](https://discourse.vtk.org/u/11112)
#### Post date: [May 13, 2021, 5:52am UTC](https://discourse.vtk.org/t/actor-flash-once-after-change-actor-input-connect/5642/5 "2021-05-13T05:52:15Z")

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Hi Thomas,  
Can u see know what’s the matter in my program with this picture?  
Thanks!