# vtkPropPicker not working in OSX and Qt

**URL:** https://discourse.vtk.org/t/vtkproppicker-not-working-in-osx-and-qt/8057
**Category:** Development
**Created:** [March 15, 2022, 1:03pm UTC](https://discourse.vtk.org/t/vtkproppicker-not-working-in-osx-and-qt/8057 "2022-03-15T13:03:54Z")
**Posts on this page:** 1
**Showing post:** 2

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### Author: ![lassoan](https://discourse.vtk.org/user_avatar/discourse.vtk.org/lassoan/32/50_2.png) [@lassoan](https://discourse.vtk.org/u/lassoan)
#### Post date: [March 17, 2022, 5:40am UTC](https://discourse.vtk.org/t/vtkproppicker-not-working-in-osx-and-qt/8057/2 "2022-03-17T05:40:01Z")

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It seems that event position is not scaled with the correct device pixel ratio in QVTKRenderWindowInteractor. You can add logs or attach a debugger to see why that happens. Maybe using tolerance and other techniques that are used in QVTKInteractorAdapter will have to be implemented in the Python class.

You could have a look a this error report, too - maybe they are related problems:

> [@vtkPropPicker in VTK 9.1 is now returning wrong world coordinates.](https://discourse.vtk.org/t/vtkproppicker-in-vtk-9-1-is-now-returning-wrong-world-coordinates/8061):
>
> Dear people, Recently I migrated code from VTK 8.1 to 9.1. Giving or taking minor changes (mostly related to deprecated API), most of VTK code stayed the same. However, the behavior of vtkPropPicker::GetPickPosition() has changed. It now returns the wrong world pick coordinates. Here’s the code (it was fine in VTK 8.1): // Get pick position in 2D screen coordinates. int\* clickPos = this-\>GetInteractor()-\>GetEventPosition(); // Get the 3D object under the 2D screen coordinates (ray casting…

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