# Pick LPS coordinate from 3d model

**URL:** https://discourse.vtk.org/t/pick-lps-coordinate-from-3d-model/9475
**Category:** Support
**Created:** [September 27, 2022, 7:05pm UTC](https://discourse.vtk.org/t/pick-lps-coordinate-from-3d-model/9475 "2022-09-27T19:05:15Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![dj\_96](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/d/3ec8ea/32.png) [@dj\_96](https://discourse.vtk.org/u/dj_96)
#### Post date: [September 27, 2022, 7:05pm UTC](https://discourse.vtk.org/t/pick-lps-coordinate-from-3d-model/9475/1 "2022-09-27T19:05:15Z")

</div>

I’ve loaded up an STL file that should be in LPS coordinates.  
I’m able to place spheres on the 3d mesh with:

```auto
picker = vtk.vtkCellPicker()
picker.Pick(x, y, 0, renderer)
p = picker.getPickPosition()

```

Then p is the correct location to place a coneActor to denote the point. But I want to coordinate in LPS(the coordinate system the stl is based on) too. It looks like vtk 0,0,0 is placed at the center of the model so I need that to be translated to the absolute LPS Position?