I see a pic with "A little path tracing experiment " in the descriptor of the twitter feed...what's this path tracing?
Hopefully it's not too flippant to do... this: https://en.wikipedia.org/wiki/Path_tracing
:D
This is probably the key take-away quote:
"Path tracing is a computer graphics ... method of rendering images of three-dimensional scenes such that the global illumination is faithful to reality." and "When combined with physically accurate models of surfaces, accurate models of real light sources (light bulbs), and optically-correct cameras, path tracing can produce still images that are indistinguishable from photographs."
So basically it's a different (and better, in most respects) approach to rendering than what TG uses now. Path Tracing is becoming the industry standard for rendering software.
- Oshyan
Quote from: Oshyan on October 13, 2016, 03:44:16 PM
Hopefully it's not too flippant to do... this: https://en.wikipedia.org/wiki/Path_tracing
:D
This is probably the key take-away quote:
"Path tracing is a computer graphics ... method of rendering images of three-dimensional scenes such that the global illumination is faithful to reality." and "When combined with physically accurate models of surfaces, accurate models of real light sources (light bulbs), and optically-correct cameras, path tracing can produce still images that are indistinguishable from photographs."
So basically it's a different (and better, in most respects) approach to rendering than what TG uses now. Path Tracing is becoming the industry standard for rendering software.
- Oshyan
Not at all, thanks for the link and the summary. So is TG thinking along these lines?
An extended version of the algorithm is realized by volumetric path tracing, which considers the light scattering (the intriguing part) of a scene.
Due to its accuracy and unbiased nature, path tracing is used to generate reference images when testing the quality of other rendering algorithms. In order to get high quality images from path tracing, a large number of rays must be traced to avoid visible noisy artifacts.
this is intriguing and scary (in italics) all at once
No comment :P
- Oshyan
That is a very nice looking experiment, I have to say. Can Matt state any stats on rendering time, etc... on that scene? Not much noise present there.
It's way too early to quote render times. Don't hold your breath, but it's nice to see things evolving. :)
- Oshyan
Not a problem. It is very nice and that in and of itself is enough.
Sorry for stirring the pot Oshyan...
Quote from: bobbystahr on October 13, 2016, 05:38:02 PM
An extended version of the algorithm is realized by volumetric path tracing, which considers the light scattering (the intriguing part) of a scene.
Due to its accuracy and unbiased nature, path tracing is used to generate reference images when testing the quality of other rendering algorithms. In order to get high quality images from path tracing, a large number of rays must be traced to avoid visible noisy artifacts.
this is intriguing and scary (in italics) all at once
As a frequent user of Blender, I can attest to this. Takes some sleight-of-hand to avoid that noisy render, including (sometimes) a blur filter node added to the render output. It's doable, though, with the right hardware.
QuoteIn order to get high quality images from path tracing, a large number of rays must be traced to avoid visible noisy artifacts.
Seems like a developing trend is to employ some sophisticated post processing filtering (not blurring) to the image after rendering so less rays need to be fired into the scene enabling quicker render times. Renderman does this (very well!) and a standalone prog called Atlus works with a lot of renderers.
Quote from: digitalguru on December 07, 2016, 05:54:49 PM
Seems like a developing trend is to employ some sophisticated post processing filtering (not blurring) to the image after rendering so less rays need to be fired into the scene enabling quicker render times. Renderman does this (very well!) and a standalone prog called Atlus works with a lot of renderers.
You can bet that I'll try to do something similar.
Matt
Progressive Monte Carlo Rendering to reduce noise? Metropolis light transport? So are we thinking possibilities using BRDF and BSDF?
You might also be interested to know that our holiday sale image was rendered using the in-development path tracer. The "snow" is clouds... :D
https://twitter.com/terragen/status/806625957058445312
- Oshyan
Quote from: Oshyan on December 08, 2016, 03:26:06 AM
The "snow" is clouds...
https://twitter.com/terragen/status/806625957058445312
- Oshyan
I tried that once but I only could get it to work(more or less) on a flat plain. :-\ Clouds seem to be ideal for making snow because they have so much in common, unfortunately you can't add specularity to clouds (isn't it?)
You could pop in another cloud layer, lower quality and density and increase the color to 2 or so, you could get some sort of sparkling effect.
Quote from: Oshyan on December 08, 2016, 03:26:06 AM
You might also be interested to know that our holiday sale image was rendered using the in-development path tracer. The "snow" is clouds... :D
https://twitter.com/terragen/status/806625957058445312
- Oshyan
That looks nice. Curious, any chance to see the difference with a render from TG4 without the path tracer Oshyan?
This is indeed mighty interesting!!!!
You're always in for a treat with Matt at the steering wheel :o
Any substantial difference between path-tracing and ray-tracing? They sound quite a bit like the same thing.
Quote from: Upon Infinity on December 08, 2016, 10:25:08 AM
Any substantial difference between path-tracing and ray-tracing? They sound quite a bit like the same thing.
found this article online which helps understanding both conceptd
http://home.lagoa.com/2014/04/ray-tracing-vs-path-tracing-in-plain-english/
Interesting, but I hope the path tracing isn't going to slow down a render too much, compared to ray traced renders....
Quote from: Dune on December 08, 2016, 12:00:26 PM
Interesting, but I hope the path tracing isn't going to slow down a render too much, compared to ray traced renders....
My thought eggs ackley
Quote from: Dune on December 08, 2016, 12:00:26 PM
Interesting, but I hope the path tracing isn't going to slow down a render too much, compared to ray traced renders....
One of the key realisations I've had is this: if you're already rendering with very high anti-aliasing, you're already half way towards being able to path trace (brute force GI) without necessarily adding more noise.
Some of the best vegetation renders use AA of 10 or more. At this level you're getting into the territory of hundreds of samples per pixel. If the renderer then chooses to bounce some(*) of those rays off into the scene to pickup GI it might double the render time but you're rewarded with crisply detailed multi-bounce GI. At AA16 it can look incredibly good. If you only render at lower AA around 2 to 6, path tracing will be noisy so you won't want it for final renders. But I'll let you choose whether to use path traced GI or not.
(*) how many rays and where... this is where the art meets the science.
Matt
Well that certainly explained a lot, thanks Matt...having the choice will be handy if not necessary.
Quote from: Matt on December 08, 2016, 02:36:17 PM
One of the key realisations I've had is this: if you're already rendering with very high anti-aliasing, you're already half way towards being able to path trace (brute force GI) without necessarily adding more noise.
Some of the best vegetation renders use AA of 10 or more. At this level you're getting into the territory of hundreds of samples per pixel. If the renderer then chooses to bounce some(*) of those rays off into the scene to pickup GI it might double the render time but you're rewarded with crisply detailed multi-bounce GI. At AA16 it can look incredibly good. If you only render at lower AA around 2 to 6, path tracing will be noisy so you won't want it for final renders. But I'll let you choose whether to use path traced GI or not.
(*) how many rays and where... this is where the art meets the science.
Matt
This looks extremely promising!
It might be too early to ask but what about the shaders? Would you still be able to "update" the default shader or would this require a complete rework?
Matt may get your question, but I'm not sure I understand what you mean about updating the default shader.
- Oshyan
Quote from: Oshyan on December 08, 2016, 06:27:25 PM
Matt may get your question, but I'm not sure I understand what you mean about updating the default shader.
- Oshyan
That might be in reference to hannes recent post about using one texture map for multiple parts and the automation of sorts of this.
Quote from: KyL on December 08, 2016, 05:47:52 PM
This looks extremely promising!
It might be too early to ask but what about the shaders? Would you still be able to "update" the default shader or would this require a complete rework?
All existing shaders will be made to work with new rendering modes, with almost no changes needed from the user. Specular/reflectivity settings in the Default Shader are automatically used to control glossy reflections in the path tracer.
Matt
Thanks a lot for your explanation, Matt. Choice is very much appreciated, as for my work I hardly ever render with AA larger than 6. But I'm really curious about differences in appearance. Is it too early to ask for a comparison render?
Quote from: Dune on December 09, 2016, 01:43:31 AM
as for my work I hardly ever render with AA larger than 6.
It makes a visible difference.
Matt
Quote from: Dune on December 09, 2016, 01:43:31 AM
But I'm really curious about differences in appearance. Is it too early to ask for a comparison render?
Yes, we're not ready for that yet :-X
I'll check the AA out again, and meanwhile, wait in great patience :) Good luck.
@ Oshyan
Quote from: Matt on December 08, 2016, 09:23:18 PM
All existing shaders will be made to work with new rendering modes, with almost no changes needed from the user. Specular/reflectivity settings in the Default Shader are automatically used to control glossy reflections in the path tracer.
Matt
That's exactly what I meant :)
Thanks Matt, glad to hear this!
We let you work now :p