(L) [2012/11/01] [tby tuomlarsen] [Path tracing 101] Wayback!Hello!
I'm totally new to all this, please bear with me: I implemented my first path tracer, it only uses spheres and needs to shoot *a lot* of rays to see something at all when the light source is small. Now I would like to add some features which are considered "essential" but I have many questions about them:
(I'm interested in simple features, i.e. I know I can get better rendering from MLT and what not but such thing are currently totally over my head, so, I'm going through this step by step....)
- Camera. What is a "pin hole camera"? Why can't I just shoot rays into scene from screen pixels in the camera direction?
- Tone mapping. Do I need it? If I were to use "linear" tone mapping isn't it the same as using weaker light source? If I understand it correctly, it is kind of auto-exposure technique - doesn't it create problem, say, when I want to render under-exposed picture?
- Acceleration structure. I would like to add triangle primitive so I guess this is by far the most "essential" feature. I saw many articles on which one to choose and the all differ in conclusions [SMILEY :)]. So, if my scenes are static and I want to keep things simple, which one should I try? BVH, KD-Tree, Octree, something else?
- Light. I saw at [LINK http://kevinbeason.com/smallpt/#mods] that adding "explicit light sampling" speed-up the rendering considerably. As the source code for it is a bit unreadable for me - what is it? Are there any tutorials or articles about it? I guess this is the other "essential" feature next to the acceleration structure, right? How does it work - when a light bounces off a surfaces I just randomly choose whether I go somewhere else or towards a light?
- Materials. And this is something I totally don't understand. All a material does is to affect how a way bounces off its surface? I read about "hemisphere" sampling and "cosine" sampling but so far I'm lost on this one...what are they? Does it somehow relate to previous paragraph about light searching?
- I also read about using "pseudo-random" numbers, as opposed to using "random" ones, as it reduces noise (?). But where do I use them? In pixel antialiasing? For location of sub-pixels for ray shooting from camera? Or for choosing the next direction for this "bouncing off" material?
- Else. What else do you consider as "essential"?
Thank you very, very much in advance!
(L) [2012/11/01] [tby ingenious] [Path tracing 101] Wayback!It will be better both for you and the other forum members if you just get a book that explains all these things. Your post above sounds to me a bit like: "Hey, chemists, I'm new to chemistry, I mixed vodka and wine successfully last night, and now I want to know all the basics in chemistry to be able to make some great cocktails! Tell me everything you consider essential in chemistry" [SMILEY :mrgreen:]
So, get a book like "Physically Based Rendering: From Theory to Implementation", eat it up, and then people will be happy to help you with questions that are not answered in the book.
(L) [2012/11/02] [tby Dade] [Path tracing 101] Wayback!>> ingenious wrote:So, get a book like "Physically Based Rendering: From Theory to Implementation", eat it up, and then people will be happy to help you with questions that are not answered in the book.
[LINK http://www.pbrt.org/]