My Grandma always used to say, "If you want to learn about thin film interference, watch Christopher 3D." Wise words. Bless her soul and bless Christopher 3D 🙌
Kind of random, but that HDRI is the GOAT. On PolyHaven, all of them have generic names based on the location except for that one. "THE SKY IS ON FIRE!" The guy who made it clearly knew it was 'lit', both literally and figuratively. Noticed it made the cut for some paid addons too, like Materialiq.
Fantastic tutorial again, thanks a lot Chris ! Especially the last part on metalic equivalent with IOR on very high values was something that I was searching for a long time.👍 On the animation part of the tutorial, you should use the 4d parameter of the noise texture to get the W parameter that is perfect for an evolving effect kind of noise. Because 0 to 1 animation in distortion will result on a very different noise from start to finish.
One minor nitpick in the explanation part around 6:38 . Partially destructive interference doesn't change the color of the reflected light, it just reduces the intensity. The reason we get a rainbow of colors with thin film intereference is that the incident light is usually white, and is composed of all the colors, and constructive interference for different wavelengths happens at different angles. You can check this if you make the light source red, green or blue (assuming Blender's thin film interference is physically based), you will still get interference bands, but they're all of the same color, the color of the source.
When you use the Node Wrangler addon it is not necessary to press Shift+W and choose the texture setup from the menu. Just press Ctrl+T when the Background node is selected amd the texture setup will be added automatically. And it is not necessary to switch to Material Preview mode if you want to preview a noise texture... this works in rendered view as well, and since directly connecting it to the Material Output is working like an Emission shader, there is no noise previewing even at low samples.
Very clever implementation for interference color on anodized metal! Thanks for the detailed tutorial. Should work great for rendering products with iridescence or hologram film qualities. I'm not sure if thin-film can approximate it but I do hope Blender grants us glass dispersion (plus dispersion caustics) sooner or later.
Yeah, proper dispersion is a whole separate thing. Glass type objects do need some attention. They also need proper nested dialectric support which I believe has had some work done already. But yes, dispersion would be great.
Great tutorial, i was a little confused about the thin film not working on metallic surfaces when 4.2 was released but like you i figured out that you can up the IOR to simulate a metallic surface although not physically accurate. hope they update it to work with metallic in the future.
yeah, I hope they do engineer it to work with metals. I guess it has something to do with the metal model they're suing which has to be engineered a bit differently to be physically correct, or at least physically plausible. I suspect it'll work better than our IOR hack approach.
@@christopher3d475 That is indeed the case, more or less. Except if you ask the devs, it's their metallic model that's the hacky one XD And that's the issue Lukas Stockner has with partnering metallic with TFI at the moment. The metallic mode in the Principled BSDF is already very hacky, so to then hack TFI into it as well is just going to make messy code even worse. The plan is to replace the current metallic mode with something much better down the track, namely something that actually accounts for differing IOR's for red, green, and blue channels and includes proper N and K (metallic refractive index and extinction coefficients) inputs. I think Alaska already has a couple of prototypes up and running.
@@Arjjacks That's great that they're moving to a more physically correct approach to the metal. I think using N+k would be a smart move since those are actual measured values for the purists who want that kind of control.
@@christopher3d475 Yeah, it's pretty exciting. Alaska's got three new nodes in the works at the moment, one using the current F82 Tint model found in the Principled shader, an "Artistic Conductor" with artist friendly inputs that converts to N and K values under the hood, and a "Physical Conductor" with the N and K coefficients exposed as vector inputs.
Your content is amazing, Where can I learn this sort of material more in depth? I.e. to really understand the physics and mathematics behind all components of the BSDF?
Can there even be "thin film interference" in metals? Metal or conductive is not mentioned on wiki. Logically speaking, reflections in metals happens within a few atoms of thickness, way thinner than the nano scale that applies here. I'm not sure. Might be a useful fake approach for heat treatment and such, but I don't see it as a valid approach to anodized metals. For previewing number values in shaders, switch to raw view transform with none as the look. Avoids the applied gamma curve and dark/bright are more evenly distributed. Test this by mapping a gradient 0-1 snap 0.025 to a rectangle. With raw/none, you can see the variations also in the high end. For noise and its settings, you might want to make sure you're not clipping beyond the desired 0-1 range. Simple 1 check does the trick.
The interference doesn't happen "in" the material but rather on the surface, hence the name "thin film". Thin film interference on metals is certainly possible and is usually caused by oxidization (in the case of heat treatment), or an oil-like substance on the surface of the metal.
@@Nacreous01 that's why I don't understand reflections to, I just write 0, 10, 50, or 100. that's why physics is important only for physicists, not 3D designers
My Grandma always used to say, "If you want to learn about thin film interference, watch Christopher 3D." Wise words. Bless her soul and bless Christopher 3D 🙌
This is more than a Blender tutorial. Thank you for the masterclass!
best blender teacher on youtube ive seen so far
Oooo, i remember doing this in Luxrender 12 years ago, i was so happy to see those bubbles when the render finally finished half a day later
Thanks. These videos take away most of the guess work when working with Blender parameters.
I came here to learn about the film interference feature and learn I did! Great video - no blabla but everything that matters.
Consistently the best Blender tutorials around. Thank you.
The metallic cheat is rather interesting, I was able to model anodized titanium (IOR 2.16) using this method. Really neat!
Super interesting and useful, thanks for making it understandable for us muggles!
Kind of random, but that HDRI is the GOAT. On PolyHaven, all of them have generic names based on the location except for that one. "THE SKY IS ON FIRE!" The guy who made it clearly knew it was 'lit', both literally and figuratively. Noticed it made the cut for some paid addons too, like Materialiq.
Fantastic tutorial again, thanks a lot Chris ! Especially the last part on metalic equivalent with IOR on very high values was something that I was searching for a long time.👍
On the animation part of the tutorial, you should use the 4d parameter of the noise texture to get the W parameter that is perfect for an evolving effect kind of noise. Because 0 to 1 animation in distortion will result on a very different noise from start to finish.
The 4D noise is a great tip, thanks for that.
Man! Your visual presentation are spot-on. I appreciate the efforts behind it
One minor nitpick in the explanation part around 6:38 . Partially destructive interference doesn't change the color of the reflected light, it just reduces the intensity. The reason we get a rainbow of colors with thin film intereference is that the incident light is usually white, and is composed of all the colors, and constructive interference for different wavelengths happens at different angles. You can check this if you make the light source red, green or blue (assuming Blender's thin film interference is physically based), you will still get interference bands, but they're all of the same color, the color of the source.
Merci pour ce tuto extraordinaire, j'ai beaucoup appris.
This is incredible. Thank you so much Chris
Thank you for the great tutorial.
原理讲的很清楚，理解的更深刻了
When you use the Node Wrangler addon it is not necessary to press Shift+W and choose the texture setup from the menu. Just press Ctrl+T when the Background node is selected amd the texture setup will be added automatically. And it is not necessary to switch to Material Preview mode if you want to preview a noise texture... this works in rendered view as well, and since directly connecting it to the Material Output is working like an Emission shader, there is no noise previewing even at low samples.
Amazing tutorial, thank you!
Handy and instructive! Thank you!! 🙏🏻🙏🏻🙏🏻
That was an amazing video!
Very clever implementation for interference color on anodized metal! Thanks for the detailed tutorial. Should work great for rendering products with iridescence or hologram film qualities. I'm not sure if thin-film can approximate it but I do hope Blender grants us glass dispersion (plus dispersion caustics) sooner or later.
Yeah, proper dispersion is a whole separate thing. Glass type objects do need some attention. They also need proper nested dialectric support which I believe has had some work done already. But yes, dispersion would be great.
Great tutorial, i was a little confused about the thin film not working on metallic surfaces when 4.2 was released but like you i figured out that you can up the IOR to simulate a metallic surface although not physically accurate. hope they update it to work with metallic in the future.
yeah, I hope they do engineer it to work with metals. I guess it has something to do with the metal model they're suing which has to be engineered a bit differently to be physically correct, or at least physically plausible. I suspect it'll work better than our IOR hack approach.
@@christopher3d475 That is indeed the case, more or less. Except if you ask the devs, it's their metallic model that's the hacky one XD And that's the issue Lukas Stockner has with partnering metallic with TFI at the moment. The metallic mode in the Principled BSDF is already very hacky, so to then hack TFI into it as well is just going to make messy code even worse. The plan is to replace the current metallic mode with something much better down the track, namely something that actually accounts for differing IOR's for red, green, and blue channels and includes proper N and K (metallic refractive index and extinction coefficients) inputs. I think Alaska already has a couple of prototypes up and running.
@@Arjjacks That's great that they're moving to a more physically correct approach to the metal. I think using N+k would be a smart move since those are actual measured values for the purists who want that kind of control.
@@christopher3d475 Yeah, it's pretty exciting. Alaska's got three new nodes in the works at the moment, one using the current F82 Tint model found in the Principled shader, an "Artistic Conductor" with artist friendly inputs that converts to N and K values under the hood, and a "Physical Conductor" with the N and K coefficients exposed as vector inputs.
Your content is amazing, Where can I learn this sort of material more in depth? I.e. to really understand the physics and mathematics behind all components of the BSDF?
so... this is the closest thing in nature we have to z-fighting
But why is it an own Slot on the BSDF? Is it as important as emission or roughness? I am quite confused
It seems that it don't work on Eevee nex. Or you have the answer for it:)?
Yeah, this is specific raytracing technology in Cycles.
Has anyone been able to recreate the beetle carapace? Is the final tutorial about metal with thin film interference the best starting point?
If you want to examine my beetle file I can send it to you. Currently think film is really best done on non-metallic surfaces.
@@christopher3d475 That would be awesome. What's the best way for you to transfer?
@@cmysliwiec Send me an email, it's in the About area of my channel.
thank you daddy
Can there even be "thin film interference" in metals? Metal or conductive is not mentioned on wiki.
Logically speaking, reflections in metals happens within a few atoms of thickness, way thinner than the nano scale that applies here.
I'm not sure. Might be a useful fake approach for heat treatment and such, but I don't see it as a valid approach to anodized metals.
For previewing number values in shaders, switch to raw view transform with none as the look. Avoids the applied gamma curve and dark/bright are more evenly distributed.
Test this by mapping a gradient 0-1 snap 0.025 to a rectangle. With raw/none, you can see the variations also in the high end.
For noise and its settings, you might want to make sure you're not clipping beyond the desired 0-1 range. Simple 1 check does the trick.
The interference doesn't happen "in" the material but rather on the surface, hence the name "thin film". Thin film interference on metals is certainly possible and is usually caused by oxidization (in the case of heat treatment), or an oil-like substance on the surface of the metal.
I understood nothing
how come?
@@Nacreous01 that's why I don't understand reflections to, I just write 0, 10, 50, or 100. that's why physics is important only for physicists, not 3D designers
@@Nacreous01
...but I agree that this information is important
@@Nacreous01 to deep info ;)
@@Nacreous01
in the final project, no one will ask about physics... the client will care if it is similar to bubbles or not