# Can the VTK get the world coordinates of the vertices in the read model in the OpenGL shader?
**URL:** https://discourse.vtk.org/t/can-the-vtk-get-the-world-coordinates-of-the-vertices-in-the-read-model-in-the-opengl-shader/5325
**Category:** Support
**Created:** [March 5, 2021, 3:04am UTC](https://discourse.vtk.org/t/can-the-vtk-get-the-world-coordinates-of-the-vertices-in-the-read-model-in-the-opengl-shader/5325 "2021-03-05T03:04:17Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Jone7](https://discourse.vtk.org/u/Jone7)
#### Post date: [March 5, 2021, 3:04am UTC](https://discourse.vtk.org/t/can-the-vtk-get-the-world-coordinates-of-the-vertices-in-the-read-model-in-the-opengl-shader/5325/1 "2021-03-05T03:04:17Z")
I want to use the world coordinates of the model to do the lighting calculation, and I saw in VTK opengl shader can get the model coordinates and view coordinates of vertex, I think that using model matrix multiplicate model coordinates can get the world coordinate, but I have no way to get the model matrix, do you have any good way to get the world coordinates, or model matrix?
Thanks advance for you help!
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### Author:  [@dmreagan](https://discourse.vtk.org/u/dmreagan)
#### Post date: [March 5, 2021, 4:01pm UTC](https://discourse.vtk.org/t/can-the-vtk-get-the-world-coordinates-of-the-vertices-in-the-read-model-in-the-opengl-shader/5325/2 "2021-03-05T16:01:21Z")
It looks like this is only in the 2D polydata mapper, but maybe the links below can help.
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