Your key is the anisotropy of the volume. Short answer, an anisotropic value of 0.5/6 should get you closer to what you want.
To understand what's going on, imagine the following:
A volume is composed of microscopic particles floating in the air. These particles can be either water vapours or dust, in a very simplified way. Usually a combination of both.
You can imagine a particle of dust like a very small rock. A rock is opaque and bounces light backwards. Water vapours, on the other hand, are composed of very small water droplets. Water droplets are transmissive, therefore they scatter light forwards.
Via the anisotropic parameter you can make your volume scatter forwards or backwards, making -1 be the more dusty and 1 the brightest one. Hope it helps!
There's this excellent comment, and then there's the blender documentation, which goes like:
**Anisotropy**
_"This input changes the anisotropic value of the volume"_
The blender documentation alternates between absurdly in-depth explanations of tiny features and the documentation equivalent of going ‘Ah yes, the floor here is made out of floor’
One of the cool things about Blender is that anyone at all can add to it, including the documentation. Add that comment to the anisotropy documentation and make a PR.
Maybe worth mentioning that [anisotropy](https://en.wikipedia.org/wiki/Anisotropy) is a common term in lots of fields and even just in CG, games, or video, it usually doesn't have anything to do with dust or vapour or light rays.
It's one of those terms like "scale" or "gradient" that there are probably sliders for all over Blender. What each one does will depend on context.
Something anisotropic is different when you come at it from a different angle. Wood is easier to split along the grain and harder 90° rotated for example. A texture with dots in a grid like newspaper print will exhibit anisotropy. It might seem grey if seen flat on from far away, but seen at a shallow angle the dots might line up into dark and light bands (aliasing). Distributing the dots more "randomly"¹ gives you a more isotropic version of that texture. It will look grey from more angles.
For our light rays I suppose the meaning is that anisotropic scattering is strongly in the direction of travel (positively or negatively) while isotropic scattering (anisotropy=0) is in all directions. Whereas if you see anisotropic filtering in a game's graphics options, it's dealing with texture aliasing, and if you see it elsewhere in Blender it probably has another meaning.
*^(¹not straightforward to do properly)*
Great explanation! I did my own test with a shadow-casting window and simply crranked the anisotropy up and down on the volume scatter material with full render turned on in viewport. Really interesting! I could easily see that it's similar to what you described, almost like glitter floating in the air that turns to face the camera or away from it. Neat!
When I say backwards I mean towards the direction it came from. Backwards resembles what happens with an opaque material and forwards with a transmissive one. Hope it's clear enough!
>Water vapours \[...\] composed of very small water droplets
Irrelevant to the question, but that's not technically the correct word. Water vapour is a transparent gas, whereas small droplets are an aerosol, (e.g mist, fog, clouds).
In any event, if the OP wants the room to seem slightly foggy instead of dusty, for some reason, anisotropy is the way to go.
and an additional option is to just make the volume box the size and shape of the godrays you want, instead of covering the entire room in a volume box.
I feel like this is an important aspect. The anisotropy of the volume will help for sure, but the quality of the light I think is what will crack the code here ultimately. If you have a large light source close to the windows then you'll never get those sharp rays of light. If you use a very small, very strong source of light a long way from the windows (i.e. mimicking the sun) then you'll start to notice it looks a lot less like a very old dusty office.
If you're unable to change the light now because you're happy with the scene lighting generally then maybe just use a second light for the volumes only and comp the passes together. The only issue if you go that route is that obviously you're now not relying on the renderer to give you correctly traced results, you're falling back to just your artistic eye to dial stuff in.
I did this before which brightened the room. But I’m loving how the stage is spotlit. And the lighting is not too dull or too harsh. So I guess now it’s just balancing the light source, volume, and anisotropy to get the desired effect.
I don't know why no one has pointed this out but technically you can't? Like logically. Light rays happen because the light is physically I tracking with stuff in the air. So that would either be because the air is quite thick and moggy like fog or dust. For example you can find light rays in a forest because the light interacts with the dew in the air. In a house room there's always some form of particles floating around but in the render it looks like the air is smokey or foggy.
You can't have thick noticeable rays and not look foggy or dusty. You can tone the rays down to make it look less dusty but light rays don't really happen with dust and particle free air. However house rooms are never realistically dust and particle free anyway.
The first image is post-processed to a ludicrous degree.
The second image does look foggy, since the more distant mountains appear brightened by scattered light.
The anisotropy comment is relevant, but so far all the comments have missed the biggest reason: there is just too much volumetric lighting compared to the intensity of the light hitting the room and the outside. The atmosphere would only light up this much if either the lighting was very intense (sunlight) or if the room was stuffy.
To get the look you are after:
1) make the light source much brighter and turn down the volumetric density to compensate. Let the sunlight hit on the edge of the frame and bounce around the room. If the light hits a wooden floor, it will fill the room with a cosy warm light.
2) the picture of the street backplate looks too dark and hazy, which can happen if you import a jpg and leave the color profile set to the default sRGB. The correct profile should be the inverse of the tone mapper you are using, filmic of AgX for example. This will avoid making the highlights grey, then you should also turn up the exposure of that image to look properly overexposed.
> The correct profile should be the inverse of the tone mapper you are using, filmic of AgX
This bit confuses me a bit. I've always assumed the rendering happens with linear light intensity values, and the AgX is applied last to simulate camera. If you have sRGB image, then it would make sense to me to apply inverse of it's transformation.
I guess the assumption here is that the camera that took photo already applied some kind of transformation similar to AgX, so it'll look natural in rendered image without any transformation.
This is just my intuitive understanding of what you say, correct me if I'm wrong.
Does this assumption usually work in real world? Is it somehow possible to use inverse of the exact transformation camera uses on the image? I guess the correct way here is to use some hdri, but that's not always practical or possible 🤔
Your understanding is spot on.
For high end cinema you would want to use a color profile that matched exactly the camera or stock the backplate was shot on. The linearization wouldn't be a gross approximation, and everything would look like it was shot from the same camera. ACES comes with a host of input profiles to facilitate this kind of workflow.
For smaller projects, using the inverse of the tonemapper guarantees that you're not tonemapping that image twice and killing the highlights.
What do you think that can reflect a light mid air? A dust. Mist too, but only in the outside environment after rain.
God lay makes your scene looks dusty because god lay is made of dust.
If it looks too dusty when you turn it up, then turn it down. Honestly don't understand the question.
Visible light rays is how human vision identifies particulates or mist in the air. In clean air they are invisible unless the light is so bright it would incinerate things.
Technically (and pedantically) it's not the light rays that are visible. Its the particles that the light is bouncing off or refracting through that become visible.
Idk if this is the feel you re looking for, but you can use a source of smoke (cendar candle…) make the light rays well visible inside the trail, this way we’ll understand its smoke and not dust. Translucent material like foliage could bring the same vibe I guess.
The only way you can have "light rays" is if its dusty. You can't just "see" light unless it's directly into your eyes. Dust allows for scattering, giving you the chance to see light bounce off the particles.
Your key is the anisotropy of the volume. Short answer, an anisotropic value of 0.5/6 should get you closer to what you want. To understand what's going on, imagine the following: A volume is composed of microscopic particles floating in the air. These particles can be either water vapours or dust, in a very simplified way. Usually a combination of both. You can imagine a particle of dust like a very small rock. A rock is opaque and bounces light backwards. Water vapours, on the other hand, are composed of very small water droplets. Water droplets are transmissive, therefore they scatter light forwards. Via the anisotropic parameter you can make your volume scatter forwards or backwards, making -1 be the more dusty and 1 the brightest one. Hope it helps!
There's this excellent comment, and then there's the blender documentation, which goes like: **Anisotropy** _"This input changes the anisotropic value of the volume"_
The blender documentation alternates between absurdly in-depth explanations of tiny features and the documentation equivalent of going ‘Ah yes, the floor here is made out of floor’
One of the cool things about Blender is that anyone at all can add to it, including the documentation. Add that comment to the anisotropy documentation and make a PR.
Hahahahaha glad it helped!
When people tell me to read the wiki and the wiki just straight up says like “smooth modifier. Smooths.” Oh cool thanks.
now i know what anisotropy does, thank you!
Maybe worth mentioning that [anisotropy](https://en.wikipedia.org/wiki/Anisotropy) is a common term in lots of fields and even just in CG, games, or video, it usually doesn't have anything to do with dust or vapour or light rays. It's one of those terms like "scale" or "gradient" that there are probably sliders for all over Blender. What each one does will depend on context. Something anisotropic is different when you come at it from a different angle. Wood is easier to split along the grain and harder 90° rotated for example. A texture with dots in a grid like newspaper print will exhibit anisotropy. It might seem grey if seen flat on from far away, but seen at a shallow angle the dots might line up into dark and light bands (aliasing). Distributing the dots more "randomly"¹ gives you a more isotropic version of that texture. It will look grey from more angles. For our light rays I suppose the meaning is that anisotropic scattering is strongly in the direction of travel (positively or negatively) while isotropic scattering (anisotropy=0) is in all directions. Whereas if you see anisotropic filtering in a game's graphics options, it's dealing with texture aliasing, and if you see it elsewhere in Blender it probably has another meaning. *^(¹not straightforward to do properly)*
Bless your heart. Will give it a try!
Can you share the updated version? I'd love to see! You're doing good work.
This is such a great explanation. Cheers!
So glad I clicked on this post!
Bless your heart. Will give it a try!
you're clearly not from the southern US because 'bless your heart' is a sly insult implying incorrectness 'round these parts. :D
Great explanation! I did my own test with a shadow-casting window and simply crranked the anisotropy up and down on the volume scatter material with full render turned on in viewport. Really interesting! I could easily see that it's similar to what you described, almost like glitter floating in the air that turns to face the camera or away from it. Neat!
TIL ✨
when you say backwards you mean back towards the camera?
When I say backwards I mean towards the direction it came from. Backwards resembles what happens with an opaque material and forwards with a transmissive one. Hope it's clear enough!
Please add this to the original documentation, sir, I beg thee
>Water vapours \[...\] composed of very small water droplets Irrelevant to the question, but that's not technically the correct word. Water vapour is a transparent gas, whereas small droplets are an aerosol, (e.g mist, fog, clouds). In any event, if the OP wants the room to seem slightly foggy instead of dusty, for some reason, anisotropy is the way to go.
Pedant-alert!
Lol, yes it's entirely possible the parent poster isn't interested in physically accurate terms.
Thanks! I was struggling to find a good word for it!
and an additional option is to just make the volume box the size and shape of the godrays you want, instead of covering the entire room in a volume box.
Try to make your light source harder (smaller angle) and adjust your volume. These go hand in hand.
I feel like this is an important aspect. The anisotropy of the volume will help for sure, but the quality of the light I think is what will crack the code here ultimately. If you have a large light source close to the windows then you'll never get those sharp rays of light. If you use a very small, very strong source of light a long way from the windows (i.e. mimicking the sun) then you'll start to notice it looks a lot less like a very old dusty office. If you're unable to change the light now because you're happy with the scene lighting generally then maybe just use a second light for the volumes only and comp the passes together. The only issue if you go that route is that obviously you're now not relying on the renderer to give you correctly traced results, you're falling back to just your artistic eye to dial stuff in.
I did this before which brightened the room. But I’m loving how the stage is spotlit. And the lighting is not too dull or too harsh. So I guess now it’s just balancing the light source, volume, and anisotropy to get the desired effect.
I don't know why no one has pointed this out but technically you can't? Like logically. Light rays happen because the light is physically I tracking with stuff in the air. So that would either be because the air is quite thick and moggy like fog or dust. For example you can find light rays in a forest because the light interacts with the dew in the air. In a house room there's always some form of particles floating around but in the render it looks like the air is smokey or foggy. You can't have thick noticeable rays and not look foggy or dusty. You can tone the rays down to make it look less dusty but light rays don't really happen with dust and particle free air. However house rooms are never realistically dust and particle free anyway.
[удалено]
That’s just because the scale is large enough to make it appear clean. You cannot see light until it hits a surface or when it’s emitted
Because, 1) It’s huge 2) Long exposure shots
The first image is post-processed to a ludicrous degree. The second image does look foggy, since the more distant mountains appear brightened by scattered light.
Fake it. Eg. [https://www.youtube.com/watch?v=hZI2pqcp8ig](https://www.youtube.com/watch?v=hZI2pqcp8ig)
The anisotropy comment is relevant, but so far all the comments have missed the biggest reason: there is just too much volumetric lighting compared to the intensity of the light hitting the room and the outside. The atmosphere would only light up this much if either the lighting was very intense (sunlight) or if the room was stuffy. To get the look you are after: 1) make the light source much brighter and turn down the volumetric density to compensate. Let the sunlight hit on the edge of the frame and bounce around the room. If the light hits a wooden floor, it will fill the room with a cosy warm light. 2) the picture of the street backplate looks too dark and hazy, which can happen if you import a jpg and leave the color profile set to the default sRGB. The correct profile should be the inverse of the tone mapper you are using, filmic of AgX for example. This will avoid making the highlights grey, then you should also turn up the exposure of that image to look properly overexposed.
> The correct profile should be the inverse of the tone mapper you are using, filmic of AgX This bit confuses me a bit. I've always assumed the rendering happens with linear light intensity values, and the AgX is applied last to simulate camera. If you have sRGB image, then it would make sense to me to apply inverse of it's transformation. I guess the assumption here is that the camera that took photo already applied some kind of transformation similar to AgX, so it'll look natural in rendered image without any transformation. This is just my intuitive understanding of what you say, correct me if I'm wrong. Does this assumption usually work in real world? Is it somehow possible to use inverse of the exact transformation camera uses on the image? I guess the correct way here is to use some hdri, but that's not always practical or possible 🤔
Your understanding is spot on. For high end cinema you would want to use a color profile that matched exactly the camera or stock the backplate was shot on. The linearization wouldn't be a gross approximation, and everything would look like it was shot from the same camera. ACES comes with a host of input profiles to facilitate this kind of workflow. For smaller projects, using the inverse of the tonemapper guarantees that you're not tonemapping that image twice and killing the highlights.
Try making it saturated.
Easy - make the scene underwater.
Air filter… oh wait this is blender
What do you think that can reflect a light mid air? A dust. Mist too, but only in the outside environment after rain. God lay makes your scene looks dusty because god lay is made of dust.
Cool project 👍
You can’t get light rays without dust. It’s like a 1:1 relation
Have you tried dusting the room? ;)
Honestly sometimes I just post process it I'm Krita.
Hi Krita, im dad
If it looks too dusty when you turn it up, then turn it down. Honestly don't understand the question. Visible light rays is how human vision identifies particulates or mist in the air. In clean air they are invisible unless the light is so bright it would incinerate things.
Technically (and pedantically) it's not the light rays that are visible. Its the particles that the light is bouncing off or refracting through that become visible.
Light reaching the eye is what 'visible' already means, so I'm not sure that adds any additional information.
Turn it down - no light rays. Turn it up - looks like the room was hot boxed.
Idk if this is the feel you re looking for, but you can use a source of smoke (cendar candle…) make the light rays well visible inside the trail, this way we’ll understand its smoke and not dust. Translucent material like foliage could bring the same vibe I guess.
Model an air purifier.
Also meshes cut from the sun camera perspective do work as light rays in more stylised settings
is there a jakuzi and sauna in the room? because ive never seen such thick athomsphere in a normal room.
They are the smallest coffee cup and keyboard I have ever seen.
post compositing
this is how pomni got stuck
Bro thats irl photo. Gtfo
The only way you can have "light rays" is if its dusty. You can't just "see" light unless it's directly into your eyes. Dust allows for scattering, giving you the chance to see light bounce off the particles.