Your enthusiasm is infectious, I feel like when I'm watching, I'm not just learning, but being filled with an appreciation for how awesome 3D shading can really be.
I've finally found your channel again! Had to watch the whole Blender Guru's PBR tutorial just to recall exact name. Still yours is the best explanation of PBR I've ever seen since I watched it many years ago.
that moment when you find i better way of doing something and realize you have a mistake in a video you already posted. *facepalm* finally(after 7 months) found the correct way to handle roughness+fresnel interaction. its so simple yet so illusive. will cover in my fresnel video. finally not sick so i can actually record! X3 yay \o/
I don't understand... In this video you say that the roughness value must be set to the power of 0.25 to correctly simulate the fresnel/roughness relation. But in the next video (about fresnel) you say there is a better way, which does not include this feature. Does the fresnel in this new method drop linearly with the roughness going up? If so, does that mean that the graph in this video showing fresnel/roughness relation is wrong? This series is really great, thanks for creating it!
Espen Sales first method mad nothing to do with linearity. it was just some math hacks to make roughness fade fresnel properly. next video i found a better method that needed less hacking. it falls off correctly right out of the box. X3
Great job on the video. Just found your channel today and subscribed. After watching some of your older videos I'm so glad to see your PBR getting more simplified over time. :) Looking forward to your next video with practical approaches.
I'm really digging this PBR shading stuff! It's such a valuable concept that I wish I had learned about sooner! Really lookin' forward to your upcoming videos. One thing I'd really like to see covered is how to do PBR shaders for organics! How is the SSS node incorporated in a pbr skin shader? How is the translucency shader used in a leaf shader? What about hair?
Jeepster3D its on the list but further down, its pretty much just the shader you wan't and a reflection over it. things like leaves get slightly more complicated but not by much.
I've been diving deep into shading and all the maths behind it and I just have to say that this video is one of the most mistake free, and awesome videos on shading for artists
Still couldn't understand Fresnel from your explanation, so i went looking. Best example I found is, its like when your looking at water on a sunny day. If you look out across the pond, you see the reflection of the sky; but if you look at the water by your feet, you can see through to the bottom.
All Hail Blender Sensei! You are Most Worthy. These are many of the same concepts I used to teach in Classical Painting years ago. Interesting to see how they transfer over to Node Theory (and happy to not have to paint all that stuff by hand). Also Kittycat Avatar is Excellent. :)
Thanks! Very interesting, didn't think about this theory being used in shading paintings. the avatar is GamerCat from the webcomic of the same name. X3
Greetings, O Sensei! Just thought it interesting that this last week I came across no fewer than 4 new tutorials based on your work. Seems you have singlehandedly revolutionized the Fresnel Industry! Well done, sir!
I personally think that rough surface exhibit more of the fresnel effect, as oppose to masking the fresnel. The reason being that rough surface would cause light to smear and collide - also think about the bokeh effect - due to the rough surface reflecting them at random angles. This can be observed in matte surface material like fabric. Great insights for newbies on the subject tho, well done! Power gives you exponential curves... at least that's what I think you are trying to say. Cause things in the real world don't always go in a straight line.
+Hawken Fox the thing about cloth is that it isn't matte, that edge highlight is an illusion. it has to do with how you perceive brightness. when looking at cloth dead on you are seeing both the well lit tips of the fibers and the shadowed depths. your eye averages this to be a darker color. while looking at a grazing angle you only see the lit tips as they occlude the shadowed areas. making it seem brighter. making it look brighter along the edges. as for roughness making surfaces have more fresnel, not really. a little roughness makes the surface seem brighter due to scattering of the light(as you said) but it is also getting more likely to hit the surface again (and be absorbed). blender already scatters light the way you describe but it doesn't dim fresnel based on that occlusion. this is where the nodes come in. how something looks to the naked eye isn't always intuitive to what is happening to the light. thanks for the comment! I love getting comments that let me nerd out for a bit =3
Awesome tutorial, can you export an FBX with these materials, I'm trying to export it with the babylonjs exporter to play in that game angine, so I was wondering if you can bake and keep materials when you export ?
@ 12:00 I wanna say I remember reading in the book Real-Time Rendering that all materials will converge to 100% reflectivity at completely grazing angles, regardless of roughness. I was looking for it to make sure but the damn dead tree doesn't have a search feature. Can you cite your source for scaling down the entire curve to adjust for roughness?
+Reavenk fresnel doesn't change, roughness just makes it harder for the light to hit at a grazing angle. like trying to skip a stone off a wavy lake. www.marmoset.co/toolbag/learn/pbr-practice if you scroll down on the page to fresnel you can see a visual example of this in action. along with almost every PBR shader ducking edge reflections as roughness goes up. from unity to ue4 to marmoset, frostbite and even paradox. they all duck edge reflections based on roughness. otherwise it looks like your edges are glowing.
Great videos! But I think that with all this PBR talk, we are forgetting one important quality of materials and that is that not all light is reflected! And as diffuse is also a reflection (something I only recently realised...), when we use a mix shader in Blender to mix the Diffuse and Glossy, we still get all the light reflected! Now a highly polished silver reflects about 90 to 95 % of the light, copper about 40% and a rubber tire for instance only about 2%...I tried to solve this by making a custom mix shader with a simple reduction factor input (maybe I should call it a material absorption or something like that ) and have experimented a little with this in stead of the standard mix in your PBR Shaders and although there is still a lot of work and experimenting to be done, the results are already very promising and looking much more realistic. What do you think about this? Has everybody overseen this, because I have not found anything anywhere concerning this...
I think your misunderstanding the physics here. Actually diffuse is not reflected light (in terms of the glossy shader). the term reflection is just used in some physics circles to describe any surface that re-emits light that hits it. reflection in this context is light that hits a surface and bounces off. diffuse is surface diffusion. As in, light enters a surface, bounces around inside the material and eventually bounces out again. this is why, the more reflection you have, the less diffusion. if light bounces off the surface, it can't enter it and bounce around. if this light bounces around far enough in the material that we can see a difference in the entry and exit points, we use sub-surface scattering instead. but both are the same phenomena. this is why you can shine a flashlight through your fingers. light enters your hand, bounces around inside, and actually comes out the other side. some light gets absorbed and turned into heat, in the case of skin, it absorbs blue light a lot, green light a little less and red light very little. this is why the light looks red, and orange closer the the entry point of the light. Volumetric smoke is the same idea, but the surface is so low density that there is no surface to bounce off of. it enters the smoke, bounces around and exits. like a massive radius subsurface scattering.
True, but what I am trying to say is that not ALL of the light is being reflected: some of it is absorbed (or transmitted in the case of translucent or transparent materials).The amount of light being reflected (both specular and diffuse ) is called reflectance and lies roughly between 2% and 95%.(I am not talking about roughness of the surface yet). This is understandable, because if a ray of light bounces around in your scene, then, after 128 bounces for instance, it will definetely not be seen by the camera anymore because it has lost so much energy through absorption.
Hi, can u help me understanding, how metallic wood paints can be done? such as golden leaf paint on wood for classical architecture, what kind of clearcoat should it be?
Dear sir, as far as this video is about theory and not necessarily about Blender, I have a bit offtopic question. I've been using the principles you described in Blender for quite a while, and they're absolutely clear and I agree with every single word. But there is one thing which I don't understand since I started learning Renderman and Arnold - the most popular and renowned physically based renderers. You said Specular OR Reflection, but these engines have both inputs in their shaders: Specular AND Reflection, each has its Weight and Roughness, and this is where I got absolutely confused. Is it for some artistic purposes only? Your video states that single roughness, fresnel, reflectivity and diffuse are all interconnected, and changing one affects all the others. But these renderers give separate Weight, Fresnel, Amount and Roughness parameters for Diffuse, Specular and Reflection.. :) why is that? As I understood their Specular affects how light sources appear in the reflection, and Reflection is about the surrounding. But is it really physically based approach?
By the sound of it, they are artistic parameters. In my shader i make no distinction between light reflected from lights and light reflected from the environment. Which is physically correct, but many renderers let you cheat and control the two separately and often let you magnify or dim fresnel as well. In general i find these cheats often result in less useful materials. If your material isn't looking right, i generally recommend looking to the physical parameters of the surface before art hacks. That way you learn how to actually make the material consistent between scenes and lighting conditions. Having to tweak every material severely damages the ability to make material libraries and such.
I got most of my information from graphics programming papers, marmoset has some good entry level tutorials on the science. PBR in theory and PBR in practice. other than that i don't remember any, its been a long time.
Ahm, so I should watch it, although I still don't understand completely the others, I feel I'm not fluent on the node system, meaning I can copy but I can't come up with my own solutions.
***** the new series replaces the old one. you shouldn't need to watch it. i will say these are more advanced tutorials by nature(I'm hacking the builtin shading in blender) hope their still interesting even if the node stuff is confusing =3
Charlie Ringström mostly covering how everything works so when we start putting things together people can understand why certain things are done certain ways. =3
AnconeusRex i don't have access to the sphere, I'm using their slides. i recommend searching for a blender material sphere for use. there are some awesome ones out there =3
CubeRepublic yep, tried to keep it pretty artist friendly, while dielectrics have been adopted as the term for artists, conductors really hasn't. most people call it metallic, so i thought i would introduce it as that so if people got into a conversation about it with someone else they wouldn't be using different words. =3
+CynicatPro Thanks for the reply. Looking through your vids. Which video do I start at to learn about PBS in cycles, as some are marked as old? I make plants, so interested in applying this technique to foliage.
+CynicatPro Yea, the term metals is easier to grasp - but the term conductors is more prevalent in academia and more self explanatory on why they don't have subsurface/diffuse reflections.
Your enthusiasm is infectious, I feel like when I'm watching, I'm not just learning, but being filled with an appreciation for how awesome 3D shading can really be.
Glad you like it X3
Lots of beautiful works on the channel (including this one). Good job and thanks Cynicat! :)
What a great time to be alive, huh?
I've finally found your channel again! Had to watch the whole Blender Guru's PBR tutorial just to recall exact name. Still yours is the best explanation of PBR I've ever seen since I watched it many years ago.
I'm not gonna lie, the way you explain things and the vocabulary you use is amazing. I have watched your videos on PBR maybe 5 times now...
Awesome, glad you're back with more PBR stuff. You're quickly becoming one of my favorite blender tutors :)
Todor Nikolov awwww thanks! thanks for watching X3
Professional presentation you got there!
Charlie Ringström thanks!
that moment when you find i better way of doing something and realize you have a mistake in a video you already posted. *facepalm* finally(after 7 months) found the correct way to handle roughness+fresnel interaction. its so simple yet so illusive. will cover in my fresnel video. finally not sick so i can actually record! X3 yay \o/
Your videos have been a great help !
Calvin Coolridge Thanks! that's why i love making these so much X3.
You're welcome ! I actually look forward to your videos because of how rich in information they are and they're enjoyable.
I don't understand... In this video you say that the roughness value must be set to the power of 0.25 to correctly simulate the fresnel/roughness relation. But in the next video (about fresnel) you say there is a better way, which does not include this feature. Does the fresnel in this new method drop linearly with the roughness going up? If so, does that mean that the graph in this video showing fresnel/roughness relation is wrong?
This series is really great, thanks for creating it!
Espen Sales first method mad nothing to do with linearity. it was just some math hacks to make roughness fade fresnel properly. next video i found a better method that needed less hacking. it falls off correctly right out of the box. X3
Sad that you're gone dude. This was probably half a semester worth of light and material theory condensed into 30m. It was freaking great!
Great job on the video. Just found your channel today and subscribed. After watching some of your older videos I'm so glad to see your PBR getting more simplified over time. :) Looking forward to your next video with practical approaches.
***** glad your liking the content! thanks for watching! X3
I'm really digging this PBR shading stuff! It's such a valuable concept that I wish I had learned about sooner! Really lookin' forward to your upcoming videos.
One thing I'd really like to see covered is how to do PBR shaders for organics! How is the SSS node incorporated in a pbr skin shader? How is the translucency shader used in a leaf shader? What about hair?
Jeepster3D its on the list but further down, its pretty much just the shader you wan't and a reflection over it. things like leaves get slightly more complicated but not by much.
I've been diving deep into shading and all the maths behind it and I just have to say that this video is one of the most mistake free, and awesome videos on shading for artists
awww thanks!
CynicatPro hey man, how have you been doing? will we get some new videos from you anytime soon?
it's rare that i see a blender tutorial with someone who doesn't have a british accent
this is awesome!! best explanation i have seen so far! please continue to make more videos about PBR !! :D
Still couldn't understand Fresnel from your explanation, so i went looking. Best example I found is, its like when your looking at water on a sunny day. If you look out across the pond, you see the reflection of the sky; but if you look at the water by your feet, you can see through to the bottom.
+1 for the History Crash Course series. :)
Thanks for this! Can't wait for your next video.
sweet tut, thanks for sharing. The info in your tuts are always really helpful.
Love the video! So excited for your upcoming videos :D
Thank you Sir! , You are a god in your own right! thank you for empowering others.
Eli
Love your videos man, can't wait for the next one :D
***** thanks for watching! =3
All Hail Blender Sensei! You are Most Worthy.
These are many of the same concepts I used to teach in Classical Painting years ago. Interesting to see how they transfer over to Node Theory (and happy to not have to paint all that stuff by hand).
Also Kittycat Avatar is Excellent. :)
Thanks! Very interesting, didn't think about this theory being used in shading paintings. the avatar is GamerCat from the webcomic of the same name. X3
+CynicatPro Glad I don't have to as much these days...Fresnel with acrylics isn't near as fun as with PBR node 😃
Greetings, O Sensei! Just thought it interesting that this last week I came across no fewer than 4 new tutorials based on your work. Seems you have singlehandedly revolutionized the Fresnel Industry! Well done, sir!
Michael Prostka X3 its still hard to get used to having large impacts. so many ripples...
Fractal propagation
Master piece! Thank you so much for sharing!!!!!❤️
Maaan, i love your voice *-*
And clever things it produces :D
I personally think that rough surface exhibit more of the fresnel effect, as oppose to masking the fresnel. The reason being that rough surface would cause light to smear and collide - also think about the bokeh effect - due to the rough surface reflecting them at random angles. This can be observed in matte surface material like fabric.
Great insights for newbies on the subject tho, well done! Power gives you exponential curves... at least that's what I think you are trying to say. Cause things in the real world don't always go in a straight line.
+Hawken Fox the thing about cloth is that it isn't matte, that edge highlight is an illusion. it has to do with how you perceive brightness. when looking at cloth dead on you are seeing both the well lit tips of the fibers and the shadowed depths. your eye averages this to be a darker color. while looking at a grazing angle you only see the lit tips as they occlude the shadowed areas. making it seem brighter. making it look brighter along the edges.
as for roughness making surfaces have more fresnel, not really. a little roughness makes the surface seem brighter due to scattering of the light(as you said) but it is also getting more likely to hit the surface again (and be absorbed). blender already scatters light the way you describe but it doesn't dim fresnel based on that occlusion. this is where the nodes come in.
how something looks to the naked eye isn't always intuitive to what is happening to the light. thanks for the comment! I love getting comments that let me nerd out for a bit =3
Thanks for those videos! On point and informative!
great, just what I needed.
thank you
The skin shader is fantastic! But as soon I add some bump, the pores and wrinkles go black :(
Eyes have auto-white balance, that's why outside we see white light instead of light blue. ;)
Awesome tutorial, can you export an FBX with these materials, I'm trying to export it with the babylonjs exporter to play in that game angine, so I was wondering if you can bake and keep materials when you export ?
@ 12:00 I wanna say I remember reading in the book Real-Time Rendering that all materials will converge to 100% reflectivity at completely grazing angles, regardless of roughness. I was looking for it to make sure but the damn dead tree doesn't have a search feature. Can you cite your source for scaling down the entire curve to adjust for roughness?
+Reavenk fresnel doesn't change, roughness just makes it harder for the light to hit at a grazing angle. like trying to skip a stone off a wavy lake. www.marmoset.co/toolbag/learn/pbr-practice if you scroll down on the page to fresnel you can see a visual example of this in action. along with almost every PBR shader ducking edge reflections as roughness goes up. from unity to ue4 to marmoset, frostbite and even paradox. they all duck edge reflections based on roughness. otherwise it looks like your edges are glowing.
As The Beatles sang: "All you need it Principled BSDF! Na-na-na-na-naa!"
Yep. Principled BRDF was added because of this series funnily enough. =3
Great explanation. Thaks!
White snow...hmmm...Why sounds so familiar?
I think the sound here is very quiet. Please, check you recording levels!
Great videos! But I think that with all this PBR talk, we are forgetting one important quality of materials and that is that not all light is reflected! And as diffuse is also a reflection (something I only recently realised...), when we use a mix shader in Blender to mix the Diffuse and Glossy, we still get all the light reflected! Now a highly polished silver reflects about 90 to 95 % of the light, copper about 40% and a rubber tire for instance only about 2%...I tried to solve this by making a custom mix shader with a simple reduction factor input (maybe I should call it a material absorption or something like that ) and have experimented a little with this in stead of the standard mix in your PBR Shaders and although there is still a lot of work and experimenting to be done, the results are already very promising and looking much more realistic. What do you think about this? Has everybody overseen this, because I have not found anything anywhere concerning this...
I think your misunderstanding the physics here.
Actually diffuse is not reflected light (in terms of the glossy shader). the term reflection is just used in some physics circles to describe any surface that re-emits light that hits it.
reflection in this context is light that hits a surface and bounces off.
diffuse is surface diffusion. As in, light enters a surface, bounces around inside the material and eventually bounces out again. this is why, the more reflection you have, the less diffusion. if light bounces off the surface, it can't enter it and bounce around.
if this light bounces around far enough in the material that we can see a difference in the entry and exit points, we use sub-surface scattering instead. but both are the same phenomena. this is why you can shine a flashlight through your fingers. light enters your hand, bounces around inside, and actually comes out the other side. some light gets absorbed and turned into heat, in the case of skin, it absorbs blue light a lot, green light a little less and red light very little. this is why the light looks red, and orange closer the the entry point of the light.
Volumetric smoke is the same idea, but the surface is so low density that there is no surface to bounce off of. it enters the smoke, bounces around and exits. like a massive radius subsurface scattering.
True, but what I am trying to say is that not ALL of the light is being reflected: some of it is absorbed (or transmitted in the case of translucent or transparent materials).The amount of light being reflected (both specular and diffuse ) is called reflectance and lies roughly between 2% and 95%.(I am not talking about roughness of the surface yet). This is understandable, because if a ray of light bounces around in your scene, then, after 128 bounces for instance, it will definetely not be seen by the camera anymore because it has lost so much energy through absorption.
Hi, can u help me understanding, how metallic wood paints can be done? such as golden leaf paint on wood for classical architecture, what kind of clearcoat should it be?
I couldn't quite catch the name of the math website you mentioned in your video at about 15:15. Desmos? Could give that a spell-out for me? Thanks.
Ignore my request. I guess I heard it correct...typed it into Google and got the calculator...thanks.
its good shit. has saved my ass on many occasions.
Dear sir, as far as this video is about theory and not necessarily about Blender, I have a bit offtopic question. I've been using the principles you described in Blender for quite a while, and they're absolutely clear and I agree with every single word. But there is one thing which I don't understand since I started learning Renderman and Arnold - the most popular and renowned physically based renderers. You said Specular OR Reflection, but these engines have both inputs in their shaders: Specular AND Reflection, each has its Weight and Roughness, and this is where I got absolutely confused. Is it for some artistic purposes only? Your video states that single roughness, fresnel, reflectivity and diffuse are all interconnected, and changing one affects all the others. But these renderers give separate Weight, Fresnel, Amount and Roughness parameters for Diffuse, Specular and Reflection.. :) why is that? As I understood their Specular affects how light sources appear in the reflection, and Reflection is about the surrounding. But is it really physically based approach?
By the sound of it, they are artistic parameters. In my shader i make no distinction between light reflected from lights and light reflected from the environment. Which is physically correct, but many renderers let you cheat and control the two separately and often let you magnify or dim fresnel as well. In general i find these cheats often result in less useful materials. If your material isn't looking right, i generally recommend looking to the physical parameters of the surface before art hacks. That way you learn how to actually make the material consistent between scenes and lighting conditions. Having to tweak every material severely damages the ability to make material libraries and such.
Have you ever heard the tragedy of Roughness and Fresnel?
Cool vid. clarified some confusion. ;3
+DarkWolfSoul Death glad to help!
cthulhu fhtagn. Gots ta love that Lovecraft
hey CynicatPro, can you please recommend any websites and books that can help me understand the science and optics behind PBR?
I got most of my information from graphics programming papers, marmoset has some good entry level tutorials on the science. PBR in theory and PBR in practice. other than that i don't remember any, its been a long time.
Thanks!
Thank you
You have a series on this before, are these videos continuying those old series or the same?
+DuartChannel its a revisiting of the series. new method of doing roughly the same thing. this is just better. =3
Ahm, so I should watch it, although I still don't understand completely the others, I feel I'm not fluent on the node system, meaning I can copy but I can't come up with my own solutions.
***** the new series replaces the old one. you shouldn't need to watch it. i will say these are more advanced tutorials by nature(I'm hacking the builtin shading in blender) hope their still interesting even if the node stuff is confusing =3
This is the method which I've always used. What is the other method called?
Charlie Ringström Didn't know about the roughness fresnel though!
Charlie Ringström mostly covering how everything works so when we start putting things together people can understand why certain things are done certain ways. =3
I found this concept really hard when I first started out. People are going to love this series!
Thank you good sir. Me don(t')s me fedora to thee.
blenderguru anyone?
yo
Where could I get that model you're using?
AnconeusRex which one? if you mean the demo sphere, thats 3D coats demo sphere, if you mean the assets at the end, those are sculpts i made. =3
CynicatPro I was talking about the demo sphere so thanks! The sculpts look great!
CynicatPro For some reason I can't find it. Do you have a direct link?
AnconeusRex i don't have access to the sphere, I'm using their slides. i recommend searching for a blender material sphere for use. there are some awesome ones out there =3
AnconeusRex I think I saw it on blendswap.com but it's a pretty universal model, you can find it almost everywhere
bar!bar!bar!bar!bar!bar!bar!bar!bar!bar!bar!
does this have no audio?
It has audio. looks like its on your end, sorry. =/
You are right. I can now hear it. thanks :)
I thought non-dialectrics were called conductors? Great video :)
CubeRepublic yep, tried to keep it pretty artist friendly, while dielectrics have been adopted as the term for artists, conductors really hasn't. most people call it metallic, so i thought i would introduce it as that so if people got into a conversation about it with someone else they wouldn't be using different words. =3
+CynicatPro Thanks for the reply. Looking through your vids. Which video do I start at to learn about PBS in cycles, as some are marked as old? I make plants, so interested in applying this technique to foliage.
CubeRepublic i have older series but they are all outdated. i'm currently re-doing the series and organics are on the to-do list. =3
+CynicatPro Yea, the term metals is easier to grasp - but the term conductors is more prevalent in academia and more self explanatory on why they don't have subsurface/diffuse reflections.