offset clouds technique - an idea

Started by moodflow, March 13, 2008, 02:01:01 pm

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moodflow

March 13, 2008, 02:01:01 pm Last Edit: March 13, 2008, 02:06:05 pm by moodflow
One thing we can't do using the default cloud setup is create offset clouds.  Currently, the clouds flow in concentric layers around the main planet.  This makes it difficult to make clouds that truly change vertically.  The current system can do it in a way, but I discovered a way to make some radical looking clouds that are not bound to the planet.

Here is what to do:  Create a second planet.  Make the second planet's radius 0 (so its invisible), and disable its atmosphere (we don't need it).  We are going to use the second planet's clouds on the first planet.  The clouds will be offset relative to the main planet, as they will be wrapping around the second planet.  Now place the second planet wherever you want - the clouds will follow it wherever you place it.

For example, put the second planet about 10000 meters away from the render camera.  Make its cloud height 0, and its cloud depth slightly less than its distance away from the render camera.  This makes for some crazy cloud effects, as the clouds are associated with the second planet (wrapping around it), not the main planet, but are effected by the main planets atmoshere and lighting.  Move the second planet around to place the clouds in different configurations. 

Some example effects:  placing the second planet overhead creates clouds that curve "upwards" towards the second planet.  Placing the second planet way out in front of the camera makes vertical style clouds that come out of the ground on the main planet.  The options are endless.

Hopefully, someone can give this a shot and post some of their results.  I'll post what I have when I get back home in a day or two.  I've already tested it and it works well.  I hope this wasn't too confusing as its just hard to explain.

We may even be able to do this with terrain, but thats another test and topic.

http://www.moodflow.com
mood-inspiring images and music

choronr


Volker Harun

March 13, 2008, 03:06:29 pm #2 Last Edit: March 13, 2008, 03:35:35 pm by Volker Harun
It works ... and it looks very promising :-)

Edit: Attached image has 3D cumulus at 500 heigt with 500 depth

moodflow

March 13, 2008, 04:12:57 pm #3 Last Edit: March 13, 2008, 04:19:45 pm by moodflow
Yes, I have some interesting looking images that feature this (at home).  Too bad I am stuck at work.   :-[
http://www.moodflow.com
mood-inspiring images and music

Volker Harun


Saurav

Genius idea. This will open up opportunities for those 'hero clouds'.  :)

bigben

I love simple ideas that are outside the box   ;D

This does have a lot of potential

JimB

A true "Eureka" moment. I wonder what happens if you use the same fractal for the different clouds (rendering on everything right now, can't test it out). Would clouds appear to flow from one set to another, or is the fractal set to a planet's co-ordinates?
Some bits and bobs
The Galileo Fallacy, 'Argumentum ad Galileus':
"They laughed at Galileo. They're laughing at me. Therefore I am the next Galileo."

Nope. Galileo was right for the simpler reason that he was right.

Matt

Quote from: JimB on March 13, 2008, 09:07:53 pm
A true "Eureka" moment. I wonder what happens if you use the same fractal for the different clouds (rendering on everything right now, can't test it out). Would clouds appear to flow from one set to another, or is the fractal set to a planet's co-ordinates?


The fractals would flow from one to another. Cloud density lookups are performed in world/universe space. However, adjacent clouds might not blend very easily because the density cutoff thresholds would be different in each cloud at the points where the two merge.

Matt
Just because milk is white doesn't mean that clouds are made of milk.

moodflow

Quote from: JimB on March 13, 2008, 09:07:53 pm
A true "Eureka" moment. I wonder what happens if you use the same fractal for the different clouds (rendering on everything right now, can't test it out). Would clouds appear to flow from one set to another, or is the fractal set to a planet's co-ordinates?


Jim, can't wait to see your results.   8)
http://www.moodflow.com
mood-inspiring images and music

monks

Great idea! One can imagine all kinds of severe turbulences possible. Wow.

monks

Volker Harun

The attached image is one of my function-tests. A simple sine-function on the sphere.
I added a second planet within the sphere to test those clouds.

Using a planet by default instead of that sphere is possible. And in this case it would not work, as I gave the planet a 30% vertical offset to the sphere - modifying the clouds' appearance.

Consider this render as it is, a work in progress.

Volker

child@play

AWESOME!!!

finally a way to place clouds where you need them. thanks a lot moodflow
perfection is not when there's nothing more to add, it's reached when nothing more can be left out


PG

This should work for volcano's billowing out steam columns. Must try that now :D
Figured out how to do clicky signatures

Seth

amazing result ! hope to see some evolutions soon :)