# vtkCamera - What coordinate system for setting variables?

**URL:** https://discourse.vtk.org/t/vtkcamera-what-coordinate-system-for-setting-variables/3173
**Category:** Support
**Created:** [April 29, 2020, 12:33am UTC](https://discourse.vtk.org/t/vtkcamera-what-coordinate-system-for-setting-variables/3173 "2020-04-29T00:33:19Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![tchen87](https://discourse.vtk.org/user_avatar/discourse.vtk.org/tchen87/32/1548_2.png) [@tchen87](https://discourse.vtk.org/u/tchen87)
#### Post date: [April 29, 2020, 12:33am UTC](https://discourse.vtk.org/t/vtkcamera-what-coordinate-system-for-setting-variables/3173/1 "2020-04-29T00:33:19Z")

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I’m attempting to use vtkCamera for my stereo rendering application, with OffAxisProjection. The display I’m using is tilted at an angle, so I wanted to get clarity on the proper coordinate system to use for the various variables that need to be set to the camera (i.e. the EyeTransformMatrix, ScreenBottomLeft, etc). Should these all be in world space? or display space?

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### Author: ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)
#### Post date: [May 1, 2020, 12:29pm UTC](https://discourse.vtk.org/t/vtkcamera-what-coordinate-system-for-setting-variables/3173/2 "2020-05-01T12:29:42Z")

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Hello, friend,

You’ll find explanations of the camera, the various coordinate systems of 3D graphics systems (such as VTK) and the transform matrices here: [https://www.kitware.com/products/books/VTKTextbook.pdf](https://www.kitware.com/products/books/VTKTextbook.pdf) (pages 43-50). The VTK book covers the subject with enough depth so you know what you’re doing as a high-level developer for the end-user.

If want to get to the bottom of it, including the mathematical and algorithmic foundations of it, I suggest reading some good computer graphics primer such as the famous _Graphics Gems_ book: [https://www.amazon.com.br/dp/B003Z9K11Q/ref=dp-kindle-redirect?\_encoding=UTF8&btkr=1](https://www.amazon.com.br/dp/B003Z9K11Q/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1)

kind regards,

Paulo