My own custom world generating heightmap software

[Erior]

Converging oceanic produces subduction and a trench as with oceanic-continental, the corresponding volcanic arc tends to form a chain of islands. There's a lot of it in the western Pacific: Japan, the Philippines, the Marianas, the Aleutians, etc. The first two are complicated by involving triple junctions rather than just simple faults.

Yep, thanks for reminding me that ;-). Was too lazy/otherwise occupied to perform a real research in my brain

[JosMetadi]

Erior,

Actually, it would be easier to just have it set each plates type at the beginning and use that to calculate the collision types rather than a varying sea level. Thanks for the suggestion!

I'm not actually moving the continents right now (although the program has the data to do so). My goal is to generate very plausible worlds at a single moment in time rather than modelling the life cycle of a planet over millennia. I envision these worlds being used for games and stories by people who are enthusiastic about the gameplay or plot and characters, and want the kind of background realism that Tolkien created for Middle-Earth, but don't have years to devote to creating it.

On a global scale, I think that realism comes largely from tectonics and climate. In the zoomed in regions I hope to be able to create, I picture erosion and rivers, vegetation, and fractal randomness playing a much larger role. I've looked at a lot of purely fractal terrains and they never seem to feel completely real at larger scales without some additional underlying structure, which mostly seems to be created manually by artists.

[Erior]

Erior,
On a global scale, I think that realism comes largely from tectonics and climate. In the zoomed in regions I hope to be able to create, I picture erosion and rivers, vegetation, and fractal randomness playing a much larger role. I've looked at a lot of purely fractal terrains and they never seem to feel completely real at larger scales without some additional underlying structure, which mostly seems to be created manually by artists.

I completely agree with you on that point.
Still... it's a pity (mainly because the program can do that, as you say) that the future user must stick with a single state of the world. It would be interesting to watch at the steps and chose one fitting our needs.
That said, I'm already grateful that someone with programming skills actually works on generating a fictive world following more or less the rules of tectonics movements . So thanks for your work and please keep us updated!

[JosMetadi]

Been doing a lot of tweaking this week. Not sure how visible the changes even are.

FractalGlobe-22.png

FractalGlobe-24.png

[Erior]

That's nice. I think that you're getting pretty interesting shapes there. I especially like the elongated continent on the right (second image). Lots of fjord-looking spots.
Keep us updated!

[Erior]

Hi JosMetadi, are you still working on this project?
It looked (and still looks )quite interesting...

[JosMetadi]

Still working on it, although not quite as much cause of visiting family and another work project.

I've switched the user interface to a menu system (replacing the growing number of temporary buttons), made the view window scalable (separate from the resolution of the map), and did some speed optimization (the tectonics are down from 90 seconds to around 12-15).

On paper, I'm working out how to handle continental shelves because without them, erosion seems to produce too many fjords and not enough river deltas.

[waldronate]

http://www.ridgenet.net/~jslayton/cshelf/index.html shows the results that a simple split exponential will give as far as continental shelves go (the program used to create the results was Wilbur, but the concept is what's important here). It's certainly not physically "accurate" in any way, but it will get a shelf at a particular altitude with pointier mountains and flatter ocean basins. The basic idea is to pick an altitude, then everything below that point get raised to a fractional power, while everything above that point gets raised to a power greater than one. Normalizing altitudes to +/-1 first helps, too. For example, if you know the max altitude, min altitude and shelf level, and use a simple exponent of 2, then the output will be ((altitude-shelflevel)/minaltitude)^(1/2) if altitude is less than shelflevel or ((altitude-shelflevel)/maxaltitude)^2 if altitude is greater than or equal to shelflevel.

This visual approximation looks best if you run a few erosion passes afterward to get some filled-out basins and incised canyons.

[Naeddyr]

This is excellent, excellent, excellent. Keep up the good work!

[JosMetadi]

Still working on this as I have time. Refining and debugging.
FractalGlobe-31.png
FractalGlobe-32.png

Waldonrate, I tried using that formula, but found it too inflexible with a varying sea level. Thanks anyway!

My next steps will be the zooming in, and turning the erosion processing into a fractal design so that it will work as the scale changes.