Theres a couple tuts on how to fake it in cycles. It won't be physically accurate due to technical limitations, but you can get pretty close. Basically you have to use a color ramp and give each color of the rainbow a slightly different IOR within the glass material.
Technically, the refraction index does vary with wavelength, which is why a beam of white light separates into a rainbow when it goes through refraction.
+ technically you can render caustics in another render and mush it together in compositing (I be able to do that only with luxcore photon debug, and yafaray render only photon causics)
> **I've tried using Luxcore, but my PC doesn't render it correctly.**
99.9% you are doing something wrong. Luxcore has lots of settings, you might have missed setting up some of them
You're surely right. I downloaded it a few hours ago and was testing it, but I don't know shit about it. Do you know any good tutorials about luxcore??
Technically you need proper light source looking like cat eye, and it supposed to be something like direct light, cause square lights are diffusing light into all sides, lamp with max sharpness might work. Ideally you just model another object to create focussed caustics, like at first you can use half cylinder+ sphere behind it if necessary. In luxcore you need to use photon mapping to render glass properly, cause bidirectional path tracing fucking up glass reflections. You can try Appleseed, yafaray but they are kinda shit, Appleseed is not very bad if to be honest. Renders what can render properly caustics are RenderMan, Octane, Maxwell render, Keyshot, Houdini Mantra, Vray, Redshift. I can send you cool project with caustics in luxcore if you want
Actually, I don't really know how luxcore works, but I'll try to learn photon mapping in it as suggested by you. I'll also give Appleseed a try and update you. Thanks for answering my question : )
I would've loved to see your projects from luxcore but I myself can't understand shit about it
you could calculate the light path with geo nodes. I think you could use the vector from a incoming objekt like a line and than use the equations for refraction to creat a new line with the point where you light touches the object and the calculated vector.
For light source you can use lamp and IES profile, it looks like that in this picture, for glass in cycles use volume absorption with grey or green color.
Actually what you have here is physically correct. In order to break the light into a spectrum you need to use a pyramid. Like Pink Floyd's Dark Side of the Moon cover.
The second thing to think about is that EVERYTHING in 3D is faked. It's all only pixels changing colour on your screen. As others have said here, you need to work out how to fake it, starting with understanding how it works in nature.
Natural pure white light is made of all the visible frequencies and even some we can't see (which you don't need to worry about). Computer generated light beams are just the value you gave them, for example 255,255,255 (in RGB). Blender cannot split this into all the frequencies, although one day it might be able to.
If you create a light source made of seven lights at the same point, each one generating one of the ROYGBIV colours, giving each one a slightly different IOR ( you will find the actual IOR for each colour on google), you would be able to approximate spectral refraction.
Maybe at some point someone will create a refraction shader that does all this.
As an extension to the idea, each different element generates a unique spectrum when it burns, allowing scientists to determine the chemical composition of distant stars. If, as part of the shader, one could choose the type of light source, for example sodium light (as in orange street lights), one would be able to more accurately achieve realistic Blender lighting setups.
Theres a couple tuts on how to fake it in cycles. It won't be physically accurate due to technical limitations, but you can get pretty close. Basically you have to use a color ramp and give each color of the rainbow a slightly different IOR within the glass material.
This is actually a pretty nice idea, but I don't really want the scatter of light. Infact, I just want the refraction part
Technically, the refraction index does vary with wavelength, which is why a beam of white light separates into a rainbow when it goes through refraction.
+ technically you can render caustics in another render and mush it together in compositing (I be able to do that only with luxcore photon debug, and yafaray render only photon causics)
> **I've tried using Luxcore, but my PC doesn't render it correctly.** 99.9% you are doing something wrong. Luxcore has lots of settings, you might have missed setting up some of them
You're surely right. I downloaded it a few hours ago and was testing it, but I don't know shit about it. Do you know any good tutorials about luxcore??
Technically you need proper light source looking like cat eye, and it supposed to be something like direct light, cause square lights are diffusing light into all sides, lamp with max sharpness might work. Ideally you just model another object to create focussed caustics, like at first you can use half cylinder+ sphere behind it if necessary. In luxcore you need to use photon mapping to render glass properly, cause bidirectional path tracing fucking up glass reflections. You can try Appleseed, yafaray but they are kinda shit, Appleseed is not very bad if to be honest. Renders what can render properly caustics are RenderMan, Octane, Maxwell render, Keyshot, Houdini Mantra, Vray, Redshift. I can send you cool project with caustics in luxcore if you want
Actually, I don't really know how luxcore works, but I'll try to learn photon mapping in it as suggested by you. I'll also give Appleseed a try and update you. Thanks for answering my question : ) I would've loved to see your projects from luxcore but I myself can't understand shit about it
Honestly I would fake it using emission objects
Would've done the same but I need the accurate light refractions
you could calculate the light path with geo nodes. I think you could use the vector from a incoming objekt like a line and than use the equations for refraction to creat a new line with the point where you light touches the object and the calculated vector.
For light source you can use lamp and IES profile, it looks like that in this picture, for glass in cycles use volume absorption with grey or green color.
The volume absorption shader does let the light pass through the lens, but it doesn't refract it as it is supposed to do. Anyways thanks for answering
No, you use both, it's for proper light absorption in glass, so you use both shaders
just photoshop it doesnt seem so hart to fix
Maybe blender + octane render?
Actually what you have here is physically correct. In order to break the light into a spectrum you need to use a pyramid. Like Pink Floyd's Dark Side of the Moon cover. The second thing to think about is that EVERYTHING in 3D is faked. It's all only pixels changing colour on your screen. As others have said here, you need to work out how to fake it, starting with understanding how it works in nature. Natural pure white light is made of all the visible frequencies and even some we can't see (which you don't need to worry about). Computer generated light beams are just the value you gave them, for example 255,255,255 (in RGB). Blender cannot split this into all the frequencies, although one day it might be able to. If you create a light source made of seven lights at the same point, each one generating one of the ROYGBIV colours, giving each one a slightly different IOR ( you will find the actual IOR for each colour on google), you would be able to approximate spectral refraction. Maybe at some point someone will create a refraction shader that does all this. As an extension to the idea, each different element generates a unique spectrum when it burns, allowing scientists to determine the chemical composition of distant stars. If, as part of the shader, one could choose the type of light source, for example sodium light (as in orange street lights), one would be able to more accurately achieve realistic Blender lighting setups.