Constraining clouds

Started by kevnar, June 16, 2009, 09:39:46 PM

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kevnar

Is it possible to constrain a cloud to certain coordinates, or is it always a global atmosphere thing? I'd like to be able to stick just one cloud in one part of the sky and say, "Here! Stay put!" Can I do that?

neuspadrin

You can use various shaders to constrain them, such as distance shaders.

Dandelo also created a meta cloud download, which lets you build your own cloud

http://forums.planetside.co.uk/index.php?topic=3691.msg50489#msg50489
http://forums.planetside.co.uk/index.php?topic=4844.0

Tangled-Universe

Neuspadrin gave you option #1, here's #2:

Create a camera and move/position it where you want your cloud.
Create a distance shader and attach the camera to it's camera input port.
In the distance shader define the size of the distances with the far and near distance values.

Use this combination of 2 shaders as blendshader for your cloudfractal, et voila!

Martin

Goms

For #2 you have to adjust the height also. its a little bit tricky, the distance shader uses not only x/z but also the y coordinates for the distance.
Quote from: FrankB
you're never going to finish this image ;-)

schmeerlap

#4
Quote from: Goms on June 17, 2009, 04:17:41 AM
For #2 you have to adjust the height also. its a little bit tricky, the distance shader uses not only x/z but also the y coordinates for the distance.

As I understand it spherical distance mode does use all three coordinates; the clouds will be confined in the huge bubble determined by your near and far distance parameters, and that bubble's position is determined absolutely by the xyz coordinates of the camera you're using. However Z depth (planar) mode is not height dependent in the same way. The best analogy I can think of for the planar mode is that of a croupier dragging your chips away from you with his/her rake-thingy (what's the technical term for that device he/she uses to impoverish you). So, using the planar distance mode you can place a camera next to the render camera and push the clouds away from you along the path the camera is pointing. Rotating the camera on the Y axis changes the direction the clouds will be pushed away from the camera (and you).
As long as the X and Z camera coordinates approximate the render camera's you won't change the cloud placement by raising or lowering the camera (in planar distance mode). It's the direction the camera is facing (rotation on Y axis) that's important, along with the near distance and far distance parameters.

John
I hope I realise I don't exist before I apparently die.

Tangled-Universe

Quote from: Goms on June 17, 2009, 04:17:41 AM
For #2 you have to adjust the height also. its a little bit tricky, the distance shader uses not only x/z but also the y coordinates for the distance.

Correct, forgot to mention that :)