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General => Terragen Discussion => Topic started by: ares2101 on January 23, 2013, 02:11:22 PM

Title: Making a Donut-Shaped Cloud
Post by: ares2101 on January 23, 2013, 02:11:22 PM
I've looked around and I see this have been addressed before, but I'm not understanding it.  What is the simplest way to create a donut-shaped cloud?  I've got a dense localised cloud forming a disk and I can't seem to get a hole to form in its center.  I've tried putting a camera inside it and using a distance shader, but to no avail.
Title: Re: Making a Donut-Shaped Cloud
Post by: Zairyn Arsyn on January 23, 2013, 02:18:52 PM
maybe try using the painted shader?
as a blending shader, hmmm...

Title: Re: Making a Donut-Shaped Cloud
Post by: mhaze on January 23, 2013, 02:26:38 PM
Image shader! blurred white torus on a black background used as a mask for the cloud density shader.
Title: Re: Making a Donut-Shaped Cloud
Post by: Zairyn Arsyn on January 23, 2013, 02:36:53 PM
now your on your way, :)

i'm sure it would also be possible to do this with blue nodes...
but i'm not going to go there... ;)
Title: Re: Making a Donut-Shaped Cloud
Post by: cyphyr on January 23, 2013, 02:51:52 PM
Two distance shaders merged on top of each other should do it.
Plenty of other ways.
Title: Re: Making a Donut-Shaped Cloud
Post by: mhaze on January 23, 2013, 03:05:59 PM
Nice one, never seen that before let alone thought about it :)
Title: Re: Making a Donut-Shaped Cloud
Post by: mhaze on January 23, 2013, 03:06:59 PM
You colud do the same thing with 2 SSS subtracted from one another
Title: Re: Making a Donut-Shaped Cloud
Post by: cyphyr on January 23, 2013, 03:23:55 PM
I think mhaze's version is probably better :)
Title: Re: Making a Donut-Shaped Cloud
Post by: ares2101 on January 23, 2013, 05:03:47 PM
Quote from: mhaze on January 23, 2013, 03:06:59 PM
You colud do the same thing with 2 SSS subtracted from one another

How exactly do I do that?  I'm having no luck with other methods.
Title: Re: Making a Donut-Shaped Cloud
Post by: Dune on January 24, 2013, 01:32:36 AM
Like this, but then attached as blender to your cloud fractal.
Title: Re: Making a Donut-Shaped Cloud
Post by: ares2101 on January 24, 2013, 10:11:59 AM
Quote from: Dune on January 24, 2013, 01:32:36 AM
Like this, but then attached as blender to your cloud fractal.

OK, I did all that and while I see some progress, it's not working perfectly.  You can see a change in the cloud's appearance in the middle, but I can't seem to make that an actual hole.  I tried tweaking the depth of the cloud, but that didn't do much.  As a test, I attached the two SSS and merge shader to a displacement shader on the ground and got a donut shape, so I know they work.

If it helps to figure it out, if I turn off Localise on the cloud, it becomes a total overcast, so the cloud appears to not be constrained by the two SSS.
Title: Re: Making a Donut-Shaped Cloud
Post by: Dune on January 25, 2013, 04:10:20 AM
If your cloud fractal is blended by something (anything), the cloud coverage messes up things. So turn that to zero again and try to increase/decrease cloud coverage inside the fractal. I think that's the culprit.
Title: Re: Making a Donut-Shaped Cloud
Post by: ares2101 on January 25, 2013, 12:10:13 PM
Quote from: Dune on January 25, 2013, 04:10:20 AM
If your cloud fractal is blended by something (anything), the cloud coverage messes up things. So turn that to zero again and try to increase/decrease cloud coverage inside the fractal. I think that's the culprit.

OK, I'm seeing some improvement, I no longer need Localise on for it to be contained around the mountain.  However, I still can't get the hole, even after trying to tweak other stuff as well.  I'm attaching the relevant nodes, maybe that will help things.
Title: Re: Making a Donut-Shaped Cloud
Post by: Dune on January 25, 2013, 12:16:13 PM
You have to subtract one from the other 100%. The merge shader still was at 0.5.
Title: Re: Making a Donut-Shaped Cloud
Post by: ares2101 on January 25, 2013, 12:20:28 PM
Quote from: Dune on January 25, 2013, 12:16:13 PM
You have to subtract one from the other 100%. The merge shader still was at 0.5.

Oh, so that's what that value is.  Never really used merge shaders.  This is the second time today such a small thing has vexed me in a project.  Thanks Dune.
Title: Re: Making a Donut-Shaped Cloud
Post by: cyphyr on January 25, 2013, 12:24:00 PM
When you mentioned using SImple shape shaders I thought you were going for something more like this.
Title: Re: Making a Donut-Shaped Cloud
Post by: Dune on January 25, 2013, 12:38:24 PM
Same principle, isn't it? You can shape it anyway you want, even warp it in strange ways  ;)
Title: Re: Making a Donut-Shaped Cloud
Post by: ares2101 on January 25, 2013, 01:04:30 PM
Quote from: cyphyr on January 25, 2013, 12:24:00 PM
When you mentioned using SImple shape shaders I thought you were going for something more like this.

Google Death Mountain and you'll see my inspiration for this project.
Title: Re: Making a Donut-Shaped Cloud
Post by: Oshyan on January 25, 2013, 08:31:30 PM
I would suggest using the Final Density Modulator input if you're having trouble with the Coverage Adjust influencing your ring area. In fact that's the surest way to influence the cloud coverage area, which could solve some of the problems you've been having here, as the earlier solutions really should have worked.

- Oshyan
Title: Re: Making a Donut-Shaped Cloud
Post by: ares2101 on January 25, 2013, 08:45:01 PM
Quote from: Oshyan on January 25, 2013, 08:31:30 PM
I would suggest using the Final Density Modulator input if you're having trouble with the Coverage Adjust influencing your ring area. In fact that's the surest way to influence the cloud coverage area, which could solve some of the problems you've been having here, as the earlier solutions really should have worked.

- Oshyan

It's coming out nicely now.  I'll likely have a final render done by the end of the weekend.