Puttling clouds on the horizon?

Started by DeanoD, December 22, 2006, 10:15:32 PM

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DeanoD

Ello everybody!. I am trying at the moment to make a 'front' of clouds that are coming towards the camera from the horizon.. I am puzzled as to how I can limit clouds to further away then a certain distance for a specified point.. Is there a way?

???

TY in advanceos
' Dont Worry.. i crash better than anybody i know '

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Blackheart6004

How about increasing the sized of the Clouds?

Density Fractals > Scale > Featured Scale
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DeanoD

#2
Dont think it will work because I want the clouds that are on the horizon to be small compac and dense..

I am talking like in this video that was made with TG2 where the plane rolls past the camera and you see some clouds on the horizon. but nowhere else.

oops forgot the link:

http://throb.net/ss_roadster/
' Dont Worry.. i crash better than anybody i know '

Mel Gibson
Air America
Anything, Anywhere, Anytime.

Tsukiyono

seems like the majority of the clouds I make are always near the horizon. Currently I am trying to create something similar like Luc made in the cumulonimbus post, so I am upping the density and the scale sizes right now and thats where all of my clouds come out at for some reason :D

efflux

My suggestion is that you blend cloud shaders. One with few clouds and one with many, blending using another shader with large feature scale from the merge shader node. By hitting random seed on the blending cloud shader you may get a view you like. I'm not talking from experience in TG2 here but I know from using Mojoworld and what TG2 has that this might work if you can work out how to do it.

Oshyan

There are a couple things you can do. First, you can try putting a Transform shader and using the Translate function on the Cloud Layer Density Fractal (just plut the Transform in-between the Density Fractal and the Cloud Layer). The use of this is if you find a formation you like you can move it around in the scene by adjusting the translate values and essentially put it where you want it. That's only useful of course if there are no other bits that show up when you move the bit you like into position. You might be able to help with this by making your Lead-in scale larger, for larger formations, or by using a Blend Shader on your Density Fractal to make large patches of empty space, then move an empty patch over your camera so clouds are only in the distance.

An alternative method would involve using a through-camera mask. You could either use a simple gradient to mask clouds higher in the view (and therefore closer) out and keep clouds on the horizon, or you could actually come up with a scene you like and if there are nearby clouds just *paint them out* in a mask. This last approach is pretty cool and is probably how I'd do it.

First create setup the scene with some clouds where you want them, even if there are clouds where you don't want them.

Now create a new camera to use for the masking process. You'll want it in basically the same position as your current camera, but it's nice to have it separate in case you want to move your real camera.

Next create an Image Map shader and hook it to the Blend Shader input of your Density Fractal. For Projection choose Through Camera then specify the camera you just added. We won't load an image just yet. Be sure to turn on Blend By Shader in the Density Fractal.

Now do a quickie render of the scene, low detail, but with the clouds in place. Save this and open it in an image editor. Make everything white *except the clouds you don't want*, which you should make black. Hopefully they're somewhat sperate from the background clouds so you don't have to worry about making the edge of your mask look realistic - trying to paint realistic cloud edges for a mask is tough. :D

Now save your new mask in one of the formats TG2 can load and load it into the Image Map Shader. Try another test render and see if the clouds are masked out. You may need to invert the blend shader if I've gotten the masking colors reversed. If it doesn't work either way then I may have made a mistake in my instructions. ;) But hopefully you get the idea and can experiment to make it work.

Basically you're projecting a mask image straight out through the camera into the scene and using it to mask your cloud density function. This is a pretty cool technique that can be used in many situations. One interesting possibility is using it to mask populations to keep them limited only to the view of the camera at any given time, thus keeping population times and memory use down.

There's lots of power in the various shaders and functions to be toyed with. I thought for example of using a Distance Shader for this, but I couldn't get it to work as I expected. I'm guessing it's an error on my part though.

- Oshyan

oggyb

That all seems rather complicated for such a simple need :)

DeanoD

"I thought for example of using a Distance Shader for this, but I couldn't get it to work as I expected. I'm guessing it's an error on my part though."

Correctamundo old chap! ;D ;)

Distance shader works perfectly. Put it in the "Blend by shader" box at the bottom of the Density fractal for your cloud layer. Also Invert Blendshader should be checked
then set the disance shader to a Far distance of say 10000 and a near distance of say 9000.. that gives me a nice hard edge at witch the clouds stop.. exactly what I want.. The further you have those two values apart the softer the edge will be.. Also the larger those two numbers the further away from the camera the boundry will be.. Oh and dont forget to assign the camera and distance measuring type.

Looking at how the render is coming out as we speek.. looks like the clouds that have been disolved are still casting shadows.... anyone?
' Dont Worry.. i crash better than anybody i know '

Mel Gibson
Air America
Anything, Anywhere, Anytime.

Oshyan

Hehe, glad you succeeded where I failed. I just didn't get the distance values correct I guess as I had it hooked up right otherwise.

Clouds that are masked in that way definitely shouldn't be casting shadows. Can you post an image example? Is it possible it's clouds out of frame that are doing it?

- Oshyan

Njen

Quote from: DeanoD on December 23, 2006, 07:56:21 AM
"I thought for example of using a Distance Shader for this, but I couldn't get it to work as I expected. I'm guessing it's an error on my part though."

Correctamundo old chap! ;D ;)

Distance shader works perfectly. Put it in the "Blend by shader" box at the bottom of the Density fractal for your cloud layer. Also Invert Blendshader should be checked
then set the disance shader to a Far distance of say 10000 and a near distance of say 9000.. that gives me a nice hard edge at witch the clouds stop.. exactly what I want.. The further you have those two values apart the softer the edge will be.. Also the larger those two numbers the further away from the camera the boundry will be.. Oh and dont forget to assign the camera and distance measuring type.

Looking at how the render is coming out as we speek.. looks like the clouds that have been disolved are still casting shadows.... anyone?

Could you please post an example Terragen file? I am completely unable to get this working properly.

Thanks :)

Njen

Is there no one who can put a quick example of this together? I still can't get it working...

Thanks!

JimB

Quote from: njen on January 08, 2007, 10:33:43 AM
Is there no one who can put a quick example of this together? I still can't get it working...

Me neither. I'm using a Y projected image map instead.  :-\
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Njen

Quote from: DeanoD on December 23, 2006, 07:56:21 AM
"I thought for example of using a Distance Shader for this, but I couldn't get it to work as I expected. I'm guessing it's an error on my part though."

Correctamundo old chap! ;D ;)

Distance shader works perfectly. Put it in the "Blend by shader" box at the bottom of the Density fractal for your cloud layer. Also Invert Blendshader should be checked
then set the disance shader to a Far distance of say 10000 and a near distance of say 9000.. that gives me a nice hard edge at witch the clouds stop.. exactly what I want.. The further you have those two values apart the softer the edge will be.. Also the larger those two numbers the further away from the camera the boundry will be.. Oh and dont forget to assign the camera and distance measuring type.

Looking at how the render is coming out as we speek.. looks like the clouds that have been disolved are still casting shadows.... anyone?

Sorry to bring this up once again, but I want to know if anyone else but DeanoD has been able to get the distance shader working with 3D clouds? I am beginning to think it is a myth...if anyone can post a working tgd file I'd be most grateful!

chris.arceo

I got it to work by using the above steps, but i also had to uncheck the clamp far colour box. Maybe that will work for the the rest of you.

Njen