I am trying to create a function that adjusts the density of a cloud material according to the camera distance. The idea is to make the cloud layer appear more in the distance without having to use invisible spheres that make the clouds fade out.

I tried using a "distance to camera" input node and connecting it to a "map" filter which was then combined with a noise node before I connected it to the density output node. Obviously that didn't work, because I am not such a mathematical guy with the pefect understanding of the editor's logic ;-).

Any ideas?

I don't think you can do this. Wouldn't look "real" anyway. What you can do to simulate depth is to change the aerial perspective to a higher value, this will add "fake" haze and fade the clouds. depending on what you want to achieve, you can go uo to 30 (you'll have to type the number, the slider doesn't go higher then 10) to get a nice result.

Thanks bruno, but what I want to achieve is e.g. a single big cumulus cloud on the sky without having to use a Metacloud. I want to see the "profile" of the cloud layer, similar to this picture: http://www.wetterbild.de/wetterrevue/wetterwelten/fabienne/schwergewitter/schwergewitter-Dateien/image039.jpg

So it's not a matter of haze or Aerial Perspective, it's more a matter of "deleting" some clouds in the foreground in order to see more of the cloud profile in the distance.

I've been working on something similar with blending infinite terrains - but not limiting them by distance to camera.  Don't know if it will be of any use but here's a scene with an atmosphere with the clouds limited by the Y position in the scene.

Try this one as a start or to study to make you're own

Change the attached extention from .txt into .vue

Also you can use a selfmade bitmap in the function editor, make sure you uncheck the repaet into none.

Here is the one with a bitmap control

Now you have a single cloud.

(Change the .txt extention into .vue )

 You can actually create single clouds within Vue (will add some details later).

 The Gaussian Tooth node  (3) defines a blurred spherical (density) area within the cloud layer.

 

In this example I used a Rotation&Twist node (1) and set the rotation Z parameter to 315 degrees.

This way, when you use the Offset node (2) to change its position, X will move the sphere left/right and Y back/forth.

(Of course it depends on the camera angle. It works fine when the angle is set to 90/0/180).

 

The file is here

Wow, thanks to you three for the files and suggestions. I've been (and still am) a bit of busy with exams at the moment, but I will check the files at the end of the week. :-)

@ eonite Sag mal, bist du hauptberuflich Mathematiker? Das ist echt beeindruckend, wie du den Function Editor auseinander nimmst. Große Klasse.

 Super eonite! Thanks for the idea! Here's a start based on the one you shared...

 Your`re welcome, Daniel and Chipp :-)

Nice cloud, Chipp!

Daniel: No, Im not a mathematician. Just smelling the potential that lies in the function editor. To me itlike a door that has been left open, so we as users get a chance to customize the elements we want to use in our pictures.

I tried to keep my head out of the clouds, but you raise such interesting possibilities, eonite:)
The lonely clouds you and chipp showed are so cute...
It occurred to me that you can use the same tooth node to make a hole in the layer of clouds - just need to add an 'invert' math node after the tooth node.
Could come useful when you want a hole in the clouds for god rays to come through.
I know of another method to create a hole - you put a large object through the clouds, make it invisible and turn on dissolve near objects for the clouds. But it appeals to the mathematician in me to do it with a function rather than a (virtually)real object:)

I havnt tried it yet - why let reality spoil a good idea first thing in the morning...

 The inversion thing is a good idea, Artpearl. 

 

To make certain a hole is cut through the entire layer you probably need to set the Gaussian Tooth`s Z wavelength to 0 to get a cylinder instead of a sphere.

 

OMG, I sound like a teacher :-)

 Yes, it does work. Though I needed an opposite function rather than an invert, but the results speak for themselves.

Chipp, You're right of course, its called opposite not invert. The same effect is obtained by using the generic 'filter' I editing the filter function to go down instead of up. Anyhow, I'm glad it worked. I finally got around to trying it too this evening. Not only is it possible to do a single cloud or a cloud with a hole, it's possible to do both in the same image, as in the attached image of my 'dropout cloud' - that's what happens when an adventurous cloud wants to explore the sea underneath, it didnt realize it will tear a hole in the social fabric of the cloud layer:).Here I used  2 cloud layers, one with the single cloud and one with the hole. The obvious extension of this - as many single clouds as you want, each in a layer of its own. (No,  it isnt the same as using a regular layer of clouds since you can put each single cloud precisely where you want it.) Doing many holes isnt as trivial since the hole in one layer will be covered by the 'non-hole' of the other. But it should be possible  by manipulations in the function editor. That's quite entertaining:)

 Pnina, quite a wonderful image! I especially like the difference in color of our solitary friend. It almost has a night appearance with the sun actually being a full moon. Nice job!

Thanks Chipp:)  I thought I'd assign some colors to the clouds according to what I think they would feel (if they could feel). The lone cloud is either excited about his adventure or embarrassed and ashamed  about the damage he has done to his community. (There should be a green'ish tinge to the other clouds - not as pronounced- are they a bit envious?)
I thought it looks like night too, almost added stars but decided to stop fiddling:)

 They`re both beautiful, Chipp and ArtPearl!

And both pictures are good examples of what the function editor can do when paired with creativity.