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General => Terragen Discussion => Topic started by: EmDee1 on July 02, 2007, 05:14:09 PM

Title: Power fractal from Heightfield
Post by: EmDee1 on July 02, 2007, 05:14:09 PM
Is it possible in Terragen2 to use a heightfield terrain (made in World Machine for example) as a building block for a power fractal terrain?
Title: Re: Power fractal from Heightfield
Post by: Will on July 02, 2007, 05:17:40 PM
well you can apply a power fractal to the heightfield...
Title: Re: Power fractal from Heightfield
Post by: old_blaggard on July 02, 2007, 05:57:47 PM
If you're asking if it is currently possible to load a heightfield and ask Terragen to extrapolate a similar terrain out of that for the rest of the planet, the answer is no.  If you're asking if it's possible to just plop the heightfield down somewhere in a fractal terrain, the answer is yes.
Title: Re: Power fractal from Heightfield
Post by: EmDee1 on July 02, 2007, 06:12:12 PM
Thanks for the replies. Indeed I was wondering if it would be possible to "load a heightfield and ask Terragen to extrapolate a similar terrain out of that for the rest of the planet". Maybe in the future then.
Title: Re: Power fractal from Heightfield
Post by: Oshyan on July 03, 2007, 03:50:13 PM
Quote from: EmDee1 on July 02, 2007, 06:12:12 PM
Thanks for the replies. Indeed I was wondering if it would be possible to "load a heightfield and ask Terragen to extrapolate a similar terrain out of that for the rest of the planet". Maybe in the future then.

This would be an incredibly difficult thing to do at the procedural level, especially considering such advanced effects as erosion, etc. that are difficult or impossible using procedurals. So I would say it's unlikely you'll see such a function any time soon, or at least if such a thing is included it will probably be fairly limited. Right now though you can already blend a basic heightfield into a surrounding terrain of procedurals and although the character of the terrains may not be the same, with some tweaking you might make it close enough that it would work for a given scene.

- Oshyan
Title: Re: Power fractal from Heightfield
Post by: EmDee1 on July 03, 2007, 04:52:01 PM
Thanks Oshyan, I'm gonna try that out again: blending a heightfield with a power fractal terrain; maybe I gave up that aproach to soon; more tweaking then.
Title: Re: Power fractal from Heightfield
Post by: Sethren on July 03, 2007, 04:54:55 PM
Are we talking about Terrain Synthesis?

http://www.howardzzh.com/research/terrain/
Title: Re: Power fractal from Heightfield
Post by: Oshyan on July 03, 2007, 05:06:08 PM
Quote from: Sethren on July 03, 2007, 04:54:55 PM
Are we talking about Terrain Synthesis?

http://www.howardzzh.com/research/terrain/

Sort of, except that uses the actual basis heightfield to create similar terrain essentially using blended pieces. In other words it maintains both the benefits and drawbacks of heightfields in the raster domain and has a finite resolution. Covering an entire planet with that kind of algorithm would no doubt be very processor intensive and consume a huge amount of hard drive and memory space for acceptable levels of detail. These are some of the reasons why procedurals can be advantageous - higher local detail with lowered storage costs.

- Oshyan
Title: Re: Power fractal from Heightfield
Post by: EmDee1 on July 05, 2007, 02:24:20 PM
What I tried to accomplish with "the power fractal from heightfield" idea, was a bit like the way you work in World Machine: you can make a Heightfield there and then in Explorer Mode you can see that heightfield multiplicated over the entire planet. It's not possible to export that entire planet to T2, only one heightfield. So when I import that Heightfield in T2, it could have been nice to get the whole Terragen2 planet covered with that heightfield again, just as in World machine.
But as I understand now, if I want to get what I intended in the first place, I should focus more on importing one or more heightfields in T2 and build a surrounding world around it (with a power fractal for instance), that has the same feel as the imported heightfield.
Title: Re: Power fractal from Heightfield
Post by: Oshyan on July 05, 2007, 03:52:47 PM
In that case (Explorer Mode) World Machine is essentially doing just what TG2 is doing, generating an entire world procedurally in a view-dependent way (it doesn't calculate all tiles, only what is visible at any given time). It can include erosion and other non-procedural effects because it operates on a finite area at finite resolution and what is calculated is only kept in memory. If you attempted to save an entire generated Explorer session you would end up with many gigabytes of data.

At any rate yes it's best to create your base terrain however you like (in World Machine for example) and then fill in areas around it with procedurals in TG2. Unless you're going to be traversing an extremely large area in an animation this should work fine, even for scenes with very long view distances. It shouldn't be too difficult to create terrain with reasonably similar characteristics in TG2, especially for long views.

- Oshyan