title: From perspective picture to orthographic picture
body: <p>So my problem, as I said in the title is that I have an image that is in an perspective view and I to transform it into the orthographic view.</p>
  
  <p>But as far as I can understand this example :
  <a href="https://i.stack.imgur.com/q1SNB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/q1SNB.png" alt="enter image description here"></a></p>
  
  <p>the distance from the camera to the NearClip plane and to the FarClip plane is required.</p>
  
  <p>I was wondering if I'm going completly wrong and if there is a way to accomplish that without knowing those distances?</p>
  
  <p>If yes, I Suppose it's something easy such as a matrix multiplication, but after few hours of research, I turn to you searchin any help that can come...</p>
  
  <p>Thanks a lot!</p>
  
  <p>Best regards!</p>
  
  <p>EDIT : I will explain the context, maybe it can helps.
  I have a Fish-eye camera that took a panoramic picture (like below, for example)
  <a href="https://i.stack.imgur.com/Kby5K.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Kby5K.jpg" alt="enter image description here"></a></p>
  
  <p>And my final goal is to create 6 cubics (6 image that corresponde to the up, the down, right, left, front and back of a cube if you're in the cube). So I tried to use the equirectangular projection to create a picture that contains the 6 cubics.</p>
  
  <p>But the problem is that the fisheye take perspective view. So my 6 pictures are perspectives. And I want them to be ortho... :'(</p>