Path Guiding in Blender 3.4, Better Caustics and Less Noise.

Рет қаралды 19,332

Жыл бұрын

Path Guiding is based on a framework technology developed by Intel called OpenPGL. In this video I explain this technology in the recently released Blender 3.4.
NOTE: Blender 4.0 has updates to path guiding and I show that in this video: • Exciting Render Update...
#pathguiding #blender3d #blender3.4 #architecture #caustics #cycles #blendertutorial

Пікірлер: 86

@world_production Жыл бұрын

This is incredible, it’s like rendering with completely different lighting 🤩 Thank you 👏

@Intercepto Жыл бұрын

Great demo, really nice feature make images look so much better in some situations.

@tcheadriano Жыл бұрын

I usually have to disable the shadows from glassy objects. Really great news! Thank you for the examples!

@maxmaxed2887 Жыл бұрын

This is a must for Archviz. Without it Blender renders simply can't compete with any of your average Archviz software

@christopher3d475 Жыл бұрын

Agreed. Once they get this GPU enabled it'll totally rock.

@ObscureHedgehog Жыл бұрын

God I love this channel! So much in-depth info 🔥🔥🔥

@designfreedom3651 Жыл бұрын

Thank you very much for wonderful review and great examples!

@matchdance Жыл бұрын

I did render a clock animation for a project and I was always wondering what went wrong with the glass and the light sample. Thank you for the explanation! Blender is getting better and better!

@heckensteiner4713 9 ай бұрын

I didn't even know about this until I stumbled across your video! I'm surprised people aren't shouting this from the rooftops! I guess because most use GPUs, but I had an animated scene that refused to render after 10 frames on my 3080 ti. So I tried pathguiding at only 128 samples and all 200 frames fonished without a hitch. It looked about as good as the 400 sample GPU renders too and only took a liitle bit longer per frame. It will be insane if this ever gets added to GPU rendering!

@christopher3d475 9 ай бұрын

Yes. And watch my video on render improvements in the upcoming 4.0 because they've improved the path guiding function to include glossy reflections.

@Looki2000 Жыл бұрын

You can also disable caustics and make material that makes glass transparent for indirect rays to preserve reflections and strong, direct light without path guiding, but light will fly straight through the glass instead of refracting through it.

@christopher3d475 Жыл бұрын

Yep, but what's great about this new path guiding mechanism is it moves us closer towards not have to create workaround and hacks.

@robertYoutub Жыл бұрын

Perfect video for a exciting technology that is otherwise not easy to understand

@CsokaErno Жыл бұрын

You changed my whole workflow, the way I work, render and pay money for a computer hardware. This is a revolution for me. I give you a golden "thank you", big like Eiffel. Please multiply it with 100 :) What will I do with my grapich card? :D :D :D I don't need it anymore. The only disadvantage that it is slow, although I have a i7-13000k processor.

@christopher3d475 Жыл бұрын

I'm pretty sure Path Guiding will be coded to work on the GPU sooner rather than later. It's just a bit of a waiting game for that to happen.

@ZylonFPV Жыл бұрын

Excellent video man! Exciting feature, really hope it gets the full gpu acceleration soon

@rufatahmadeus1801 Жыл бұрын

great explanation and great examples

@yacineo86 Жыл бұрын

Thank u so much for sharing so intersting .

@Igoreshkin Жыл бұрын

Very good explanation. Thank you.

@eslamelmashhady4135 Жыл бұрын

very good examples

@Vospi Жыл бұрын

Thanks for a ton of demos.

@dimitrilalushi4693 Жыл бұрын

Very informative. Thanks!

@AMRedemption Жыл бұрын

Wow. Just wow.

@Hinge45 Жыл бұрын

can't wait for it to come to gpu

@jascrandom9855 Жыл бұрын

These all look so photoreal!

@TheFrogChannel Жыл бұрын

Excellent video, Chris! It's great to see another video from you. At around 7:21, you mention that path guiding allows us to crank up the value of indirect clamping. As fireflies in renders can show what the path guiding algorithms are looking for, would setting indirect clamping to 0 help make path guiding more effective? Thanks!

@christopher3d475 Жыл бұрын

I've still found that some clamping helps reduce really tough fireflies, you can just set it higher now.

@pixelkay2004 Жыл бұрын

thanks!!

@lageopedal5126 Жыл бұрын

thanks a lot! Interesting in-depth explainervideo. Could you please describe in few words or add a screenshot of the shading network of the architecturalglass of the bathroomscene?

@christopher3d475 Жыл бұрын

There's nothing special about the architectural glass, it's just a polygon with a Solidify modifer applied, .25" thickness, and then standard glass material. Meaning the Principled shader with transmission set to 100% and refraction set to 1.52. nothing special, no hacks.

@lageopedal5126 Жыл бұрын

@@christopher3d475 thanks a lot

@spastor92 Жыл бұрын

for glass y use a transparent material mixed with a glossy material blended with the fresnel node and using the camera ray node i can tell the material to not affect to the shadows so i have window reflection and 100% light passing through

@christopher3d475 Жыл бұрын

Yes, but that's a non-intuitive hack. The point of path guiding is not have to invoke things like that.

@spastor92 Жыл бұрын

@@christopher3d475 for windows make sense, you only made the material once, this is more efficient, and the result is almost the same. Also you can render in GPU. Bit this not work for caustic obviously, only windows

@christopher3d475 Жыл бұрын

@@spastor92 There's still a place for this workaround at the moment. Path guiding only works on diffuse surfaces, so any glossy-only surface will still need something like this to receive an indirect light efficiently. But they're moving in the right direction. Once they implement PG for glossy, combined with GPU support, and in combination with the upcoming revamped Principled V2 shader, the need to do workaround will be a thing of the past.

@northwind6199 Жыл бұрын

This is amazing, I've been waiting for it for such a long time! I have 2 questions: 1. If we want to see dispersion caustics, do we have to build a dispersion shader? Would that work properly with this new feature and create colorful caustics? 2. When you say "the receiving surface has to have a diffuse component", basically it just needs to not be entirely reflective or refractive, correct?

@christopher3d475 Жыл бұрын

They still don't do dispersion although there's been discussion about it on the developer forum. I haven't tried building a dispersion type node setup and see what it does. The diffuse component in the principled shader is the 'Base Color'. As long as the material as the base color it can be affected by path guiding.

@maxmaxed2887 Жыл бұрын

If you want proper dispersion and caustics, just get a Realistic Glass Shader off Blendermarket. It works perfectly and you don't even need native Blender Caustics enabled. It's also much faster than Blender caustics, even new one. In fact new caustics is still bugged and simply can't render two refracting objects inside of each other properly. That shader does all of it.

@christopher3d475 Жыл бұрын

@@maxmaxed2887 Yes, OpenPGL is a fairly new system, Intel only lists it as version 0.4. But I suspect it'll evolved fairly quickly considering their Embree libraries have continuously evolved and improved over the past decade. But thanks for the tip, I'll give the realistic shader a try.

@maxmaxed2887 Жыл бұрын

@@christopher3d475 Frankly I would be screwed without that shader lol. I do a lot of bottle/alcohol/drink renderings for a major company and that's the only way I get realistic caustics/dispersion.

@exploringrvdude7817 Жыл бұрын

@@maxmaxed2887 Blender also doesn't do nested dialectrics properly, but that's something that's been discussed in the developer forums for Cycles. I'm not sure if it's slated to be fixed in 3.5, but they're aware of the problem.

@Lucas72928 10 ай бұрын

Is the "importance map" preserved if I re-do a render or even for animations where scene geometry is static?

@kes099 Жыл бұрын

Wonderful! I have been getting used to setting up glass/water shaders by mixing a glass bsdf with a transparent bsdf driven by the Is Camera Ray property in order to let more light in (eg. I found this essential for the cornea so that the iris behind it is not just a murky blob looking like the eye of a dead fish). I am hoping that this new path guiding feature will allow a more straightforward approach of just setting a single glass shader (or principled shader with transmission on) with appropriate IOR and forgetting about it. I wonder if you have tried it with liquids. Also have you tried it with volume absorption, eg. a large window with subtle green absorption - does the green light enter the scene well?

@christopher3d475 Жыл бұрын

Yes I agree, all of these new rendering technologies are about less hacks. I'm working on a tutorial right now about the new Many Lights Sampling in 3.5 which works in hand with Path Guiding. I believe Cycles is moving in the direction of requiring less hacks for glass. The developers are aware of some of these problems. One with glass in particular is called nested dialectrics, something I hope gets solved sooner rather than later. Path Guiding does have a limitation with lots of traversals through multiple transparent refractive interfaces. Hopefully that'll get solved with time. But adding an absorption volume to a glass I do believe does get taken into account with path guiding.

@kes099 Жыл бұрын

Another tutorial I can't wait to see! Thank you so much for your contribution to the Blender community

@ZylonFPV Жыл бұрын

How do you get refractive caustics? I thought that blender removed that feature and we only have shadow caustics now

@BrentonWoods774 Жыл бұрын

Excellent video, Christopher. So Path Guiding appears to be CPU-only, do you know why that is? Also why can't we hybrid render: use CPU for path guiding and GPU for everything else?

@christopher3d475 Жыл бұрын

Yes, it's new technology that's been developed by Intel, it's based on their implementation called OpenPGL which is a composite of various academic approaches that have been developed over the years. An Intel software engineer has been working with the Blender dev team to integrate it and this first implementation of OpenPGL doesn't yet support GPU. It's planned but it just hasn't happened yet.

@BrentonWoods774 Жыл бұрын

@@christopher3d475 Thanks for your answer! I'm excited for Path Guiding on GPU.

@eclairesrhapsodos5496 Жыл бұрын

I just disable shadow and diffuse, glossy light pass in windows objects.

@christopher3d475 Жыл бұрын

That's one way of doing things, but as path guiding's implementation matures in Blender we won't have to revert to hacks or things like this which is nice.

@capricalee Жыл бұрын

I turned on Path Guiding to test my outdoor(my scene was using psa add-on and with huge plane with bump map for water shader) scene and it became super slow, don't know which one make it slow. After turn on path guiding my scene slower than before almost triple.

@christopher3d475 Жыл бұрын

The 128 training rays at the beginning can be slower and it will also depend on the complexity of your scene. It may be that PG doesn't give you benefit over the standard sampler using GPU so continue using it.

@Andy_Shust Жыл бұрын

So should you only enable PG for caustics, or is it useful if there are no caustic objects or materials in the scene? Thanks for the super informative video!

@christopher3d475 Жыл бұрын

It improves noise convergence generally. However since it's not yet GPU enabled you may still get faster convergence using standard sampling. So it depends on what you want to render.

@mnomadvfx Жыл бұрын

@@christopher3d475 Given Intel just released their frst GPU enabled Embree version (v4) I don't think it will be too long before we see GPU capabilities in this library.

@christopher3d475 Жыл бұрын

@@mnomadvfx That's fascinating, I didn't realize they had done that. But it make sense. I just hope it's sooner rather than later. The OpenPGL framework is not yet at 1.0 (I think it's 0.45) so maybe it'll get GPU enabled by a 1.0 release.

@mnomadvfx Жыл бұрын

@@christopher3d475 I've been following path guiding research for a few years so it's good that Intel made it easier to get this working in renderers - though it's been in production use as early as the VFX work for 2019's Alita: Battle Angel release. An interesting fact is that the concept of path guiding in ray tracing was based on research into simulating neutron paths / distribution in nuclear reactors from what I've read in academic papers.

@christopher3d475 Жыл бұрын

@@mnomadvfx There's a video done at the recent Blender conference done by the Intel engineer tasked with implementing OpenPGL into Cycles, it was quite interesting. He does mention that GPU is on their radar. Maxwell Render uses a more sophisticated mechanism akin to path guiding called Metropolis Light Transport, and it took them quite some time to get that up and running on GPU, so i wonder if there are some kind of technical hurdles they're working to overcome.

@ColleteralProject Жыл бұрын

That means we dont need a fake Glass shader anymore and can use the Basic glass shader in Blender? If i'm right, this will be awesome...

@christopher3d475 Жыл бұрын

Yes, this is one of the main improvements here, less of a need to hack things.

@ColleteralProject Жыл бұрын

Hope they will bring GPU support very soon. 👍

@pietroalessandrini Жыл бұрын

The problem of path guiding on the cpu is that my gpu can, for example, render a scene with 64.000 samples in 44 minutes. It's a lot of time and a lot of samples. Now if I let my cou render with path guiding for 44 minutes it will still give me a worse result than my gpu because in those 44 minutes it will have rendered much much less samples and so even with the smart sampling technique of oath guiding it is gonna give me worse results

@christopher3d475 Жыл бұрын

Well, like I mentioned in the video several places, GPU is planned and to consider this a kind of technology preview. This is based on Intel's OpenPGL framework API which is at its first release, and is part of their OneAPI. From their website it says, "Intel Open PGL is optimized for different CPU platforms, including Intel® processors with SSE, Intel® AVX-2, and Intel® AVX-512. The library also works on x86 compatible processors, support for ARM and Apple’s M1 CPUs are coming soon. Support for upcoming Intel Xe architecture GPUs and industry-standard GPUs are planned in the future."

@egorfateyev8356 Жыл бұрын

Hi, Christopher! Where can i see the material of the diamonds?

@christopher3d475 Жыл бұрын

It's just a Principled shader, transmission set to 100 and the transmission IOR is 2.41. I also turned up the reflection recursions.

@egorfateyev8356 Жыл бұрын

@@christopher3d475 ok ,thank you!

@sebbosebbo9794 Жыл бұрын

god hope Gpu comes fast.. what is with combing CPU + GPU

@christopher3d475 Жыл бұрын

I very much agree. I suspect this will become the default sampling method once that happens. You can watch the developer tasked with integrating PG into Blender here. kzfaq.info/get/bejne/eLlhfa-Ts9erqH0.html

@peihengzhang5647 Жыл бұрын

Is this available for the GPU yet

@christopher3d475 Жыл бұрын

Not that I know of.

@Darksoda-15 Жыл бұрын

Is this the same as Photon mapping?

@christopher3d475 Жыл бұрын

No, photon mapping is a bi-directional ray casting mechanism that Blender doesn't use. The Shadow Caustics mechanism is a different kind of mechanism altogether. And the kind of caustics Blender produces with normal ray tracing is just part of the unidirectional path tracing system.

@christopher3d475 Жыл бұрын

Oh, and just for clarity, photon mapping is a process where 'photon' rays are cast from a light source into the scene at surfaces that have characteristics that would produce caustics (reflective or transparent surfaces). That's why it's called bi-directional, because most of the raytracing system is a backwards process, but photon mapping starts out at the light sources and casts rays into the scene which is the opposite of what normally happens, where rays are cast from the camera and traced back to light sources. Path Guiding makes this process more intelligent.

@kingdomsaa Жыл бұрын

there is too many bugs in this version 3.4 cpu is usage 100% and don't switch to gpu 11700k 3060ti and i'm back to 3.3 when they fix it

@christopher3d475 Жыл бұрын

Yeah I noticed 3.4 seems to crash a lot. I bet they push out a 3.4.1 update fairly quickly.

@Optimus97 Жыл бұрын

Now it feels like I should've saved up for a Threadripper instead of an RTX GPU. 😵‍💫

@christopher3d475 Жыл бұрын

I'm pretty sure we'll end up with it being GPU enabled sooner rather later, just guessing.

@Optimus97 Жыл бұрын

@@christopher3d475 sure hope so

@Optimus97 Жыл бұрын

@@christopher3d475 I mean, some of Cycles features (like volumetrics) used to be CPU-only for some time and got GPU treatment later

@christopher3d475 Жыл бұрын

@@Optimus97 If you follow the developer forums, there's increasing support for various GPU core technologies and manufacturers, AMD, NVIDIA and now INTEL gpu's, in addition to their various frameworks. So I'm guessing this'll happen sooner rather than later.

@Optimus97 Жыл бұрын

@@christopher3d475 nice!!