The Algorithm That Made Me Cry

[00:00] I learned a really important life lesson  during my research. You see, I do this kind of   thing. This is ray tracing, or a light transport  simulation as we call it. And it has a superpower:  

[00:12] what is that? Well, it can simulate reality! Yes.  This is really possible - no AI needed at all. You can give it a scene, and it will simulate  the path of light rays bouncing around,  

[00:27] and give you an image of what that  scene would look like in reality.  It is absolutely insane that  we can do that. I love it. But wait, not so fast. Even if you do it  perfectly, at first, this is what it looks like. 

[00:43] Oh my, this is terrible. What is going  on? Well, that is the life lesson.   This was just simulating one ray going  through each of these pixels. That is what  

[00:55] we call one sample. One sample is not enough. If you do two samples, you get something like   this. Better? Maybe a bit. A hundred samples?  Getting better, but still, a long way off. 

[01:09] we get the beautiful final image. When you  first do it, it is a very emotional moment.  When we started, I thought this would  be impossible, and yet here it is.

[01:24] So here is two things I’d like to share with you:  one is a life lesson that I learned. Even if you   have the perfect system, at first, it might  seem that it does not work at all. But you  

[01:37] have to keep at it. And it may take a long time. And two, I’d love to share this feeling with you,   but it’s impossible, because when you  first succeed, it is beyond words.

[01:49] But wait, I think I found a way to actually share  this feeling with you. Through a song. A popular   request from you Fellow Scholars, so here it  is. And if you watch until the end of the video,  

[02:03] I’ll give you something so you can also create  a simulation like this yourself for free. Alright, with that said, this  is Károly and The Papers.

[06:36] That was so much fun, I hope you enjoyed  it as much as we did. I am not sure if I   ever heard a song written about ray tracing.  Alright, I promised you something. And it is  

[06:48] for free. I taught this master level course  at the Technical University of Vienna, and I   think knowledge should be for free for everyone.  So it’s not like the courses you see elsewhere,  

[07:00] it is completely free, in fact you can’t even pay  for it even if you wanted. Although this Fellow   Scholar was hilarious. Alright, so in this one,  I try my best to teach you the physics of light,  

[07:13] and then we code up a simulation  program together, from scratch. Enjoy!