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General => Terragen Discussion => Topic started by: sboerner on November 21, 2019, 12:29:32 PM

Title: How to expand planetary atmosphere
Post by: sboerner on November 21, 2019, 12:29:32 PM
I'd like to create a planetary atmosphere that is much larger (several diameters) than its planet. Is this possible? Once I start messing with the height controls things fall apart very quickly. I've realized that I really don't understand how they work. Can anyone define the settings and explain how they affect one another?

Haze exp height
Bluesky exp height
Ceiling adjust
Ceiling
Floor

As an example, the planet might have a radius of 2e+06, and the atmosphere a height of 2e+07.

In the meantime I'm nesting two planets, hiding the inner planet atmosphere and the outer planet surface. Not elegant but it works.
Title: Re: How to expand planetary atmosphere
Post by: Oshyan on November 21, 2019, 03:21:30 PM
The height of the visible parts of the atmosphere are essentially controlled by the Haze and Bluesky exp[onential] heights. Change those two values and you change the height of the visible atmosphere. Some semi-related info here on how the height values actually work: https://planetside.co.uk/forums/index.php/topic,26055.0.html

- Oshyan
Title: Re: How to expand planetary atmosphere
Post by: WAS on November 21, 2019, 09:00:29 PM
One thing I have noticed when ramping up the height of the atmosphere, sometimes because your displacement is more close to real-world values, is amplitudes that aren't clamped below black you'll end up with displacement below the floor of the atmosphere, creating blackness where displacement sinks below the terrain.
Title: Re: How to expand planetary atmosphere
Post by: sboerner on November 21, 2019, 09:45:40 PM
QuoteThe height of the visible parts of the atmosphere are essentially controlled by the Haze and Bluesky exp[onential] heights. Change those two values and you change the height of the visible atmosphere. Some semi-related info here on how the height values actually work: https://planetside.co.uk/forums/index.php/topic,26055.0.html
Ah, OK. I had it exactly backwards. I assumed ceiling adjust and floor controlled the height. And thank you for the link. Somehow that one didn't show up on my searches. That explains why I was getting extremely noisy results after increasing the ceiling.


Perhaps using two planets is the best solution after all, since it allows me to use normal values and avoid have to deal with any extremes.
Title: Re: How to expand planetary atmosphere
Post by: WAS on November 21, 2019, 10:56:53 PM
Quote from: sboerner on November 21, 2019, 09:45:40 PMPerhaps using two planets is the best solution after all, since it allows me to use normal values and avoid have to deal with any extremes.

What do you mean by normal values?
Title: Re: How to expand planetary atmosphere
Post by: sboerner on November 22, 2019, 04:47:57 PM
Perhaps I should have said "default." Using a (non-surface-rendered) large planet at the same location as a small (surface-rendered) planet lets me borrow the large planet's atmosphere at default or near-default values. Don't have to use extreme values and deal with resulting noise issues, etc.