<p>check this <a href="https://community.khronos.org/t/oblique-frustum/49436/6" rel="nofollow noreferrer">link</a></p>

<p>quotations ：</p>

<p>“The points (+/-1, +/-1, 1, 1) are the four corners of the view frustum on the far plane in clip space.”</p>

<p>this should be the point Q' which equals (sgn(Cx), sgn(Cy), 1, 1)</p>

CC BY-SA 4.0
2019-03-30T04:35:53.013Z
2019-03-30T04:35:53.013Z
tkokof
<p>Problem Description:</p>

<ul>
<li><p>Reference:<br>
<a href="http://www.terathon.com/lengyel/Lengyel-Oblique.pdf" rel="nofollow">Oblique View Frustum Depth Projection and Clipping</a></p>

<p>"Mathematics for 3D Game Programming and Computer Graphics" 3rd edition, chapter 5.6.</p></li>
<li><p>M is the original projection matrix. </p></li>
<li><p>Plane C is the modified near plane, and C'=transpose(inverse(M))*C is the projected plane by M.</p></li>
<li><p>Why in NDC the corner Q' of the view frustum lying opposite the plane C' is given by Q'=(Cx, Cy, 1, 1)?</p></li>
</ul>

<transformations><projections>
A question about derivation in oblique view frustum
zombielei
# A question about derivation in oblique view frustum

(Asked by: username_0 on 2016-03-06)

Problem Description:

* Reference:  
  [Oblique View Frustum Depth Projection and Clipping](http://www.terathon.com/lengyel/Lengyel-Oblique.pdf)

  "Mathematics for 3D Game Programming and Computer Graphics" 3rd edition, chapter 5.6.
* M is the original projection matrix.
* Plane C is the modified near plane, and C'=transpose(inverse(M))\*C is the projected plane by M.
* Why in NDC the corner Q' of the view frustum lying opposite the plane C' is given by Q'=(Cx, Cy, 1, 1)?

**Tags:** transformations, projections


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## 1 answers

### Answer by username_1 on 2019-03-30. Score: 0

check this [link](https://community.khronos.org/t/oblique-frustum/49436/6)

quotations ：

“The points (+/-1, +/-1, 1, 1) are the four corners of the view frustum on the far plane in clip space.”

this should be the point Q' which equals (sgn(Cx), sgn(Cy), 1, 1)


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