Rheia: one final try at ground-up worldbuilding

[Tiluchi]

I absolutely love your map Tiluchi, it's an absolute inspiration. I agree with you totally in the vector v raster debate however, one thing I have found is that after having tried Inkscape and Affinity Designer, I can't seem to get the same level of detail as Illustrator, especially doing small ,minute contours, unless of course I'm doing something wrong!

Thanks Stiophan! Good to know re: the other tools; that's not particularly surprising I suppose but it does make me feel a little better about shelling out the money for Illustrator.

I believe you can circumvent the tidal lock without magic, however. All you have to do is set the separation at 14,000,000 km, which will give you earthlike tides and not tidal lock for several billions of years. I have a rough spreadsheet to estimate values but it relies on approximations. As for climatic effects, the only thing you should be concerned about is a jovian's intense radiation belts, which would require plenty of protection in terms of magnetic field, rotation, or a dense atmosphere. To be honest, I'm not certain if I met these specifications on my last project, Kaunis.

Thanks Peter, that's very helpful! Question from a total physics newbie: would this distance make the planet look relatively small in the sky? That's about 14 times further from the planet than Ganymede is from Jupiter I believe. At any rate, I do think I'll go for magical rather than scientifically plausible explanations for it since that fits in well with the story I'm imagining at this point. Although I may change my mind, so this is good to know.

If you want an idea of how this works, here is a worldbuilding guide by Madeline James. If you are doing this, I like the WB Pasta guide, but for the creation for the atmospheric pressure cells, I recommend this for more accuracy.

Thanks Woody! I hadn't actually seen Madeline's work before but it's a very useful resource. I expect I'll be using some combination of the Azelor tutorial and the Worldbuilding Pasta tutorial for this, and this is another good one to add to the mix. I'm sure I'll read through her site later when I get past just doing the topography, but it seems all the different resources have their advantages and disadvantages, so more sources is always better.

This looks amazing! I would totally believe that your coasts and mountains were real places How long does it take you to do the topography on a continent the size of your largest here?

Thanks MrBragg! Your own work has been an inspiration for me getting back into this. I gotta be honest, doing this by hand is a LOT of work- I'd say a solid 3-4 hours per major layer in the largest continent, which is to say a solid couple weeks of long mornings just working on the little details. Still worth it for me and I'm very happy with the result so far, but only recommended if it's a world you expect to be dedicated to for a long, long time. I'm trying to do the other continents with a little less detail (50% zoom rather than 100% zoom), since I don't want to overload Illustrator as I've heard can happen, but so far it seems that that's still about 2 hours per layer, probably around 100 hours of work or so to get the whole world finished.

For your tectonics, how much detail did you go into during the course of the model? I found myself agonizing over plate interactions to the point where ~250 Ma took me years to get happy-ish with, so I want to know your secrets!

Oof, tectonics have been a major headache for me as well, and that's coming from someone who's fascinated by geology and reads articles about plate tectonics for fun. I think it took me about 2 weeks to finish this, but that's only after having gone through 900Mya of tectonic history for a different world (that I ended up scrapping in part because I wasn't satisfied with the geological accuracy). I did go into a fair amount of detail in the tectonic history, in part because reading about real-world geology has made me realize how much tectonics depends on the movements of a bunch of different microcontinents and island arcs- look at how the Mediterranean Sea, Indonesia, or Central Asia developed, for instance. If I was going to recommend any modifications to the Worldbuilding Pasta tutorial, it would be to do the world's history for less time (maybe 400-500 million years), but in more detail, especially for the past 250 million years or so. Mountain chains older than that have already been eroded away to nothing, and if you need to add some old orogenies to be uplifted, or figure out shear zones or lineaments it's probably fine to handwave them in anyway since you can guess where older active margins or orogenies would have been. Meanwhile, making recent or ongoing continental collisions messy affairs (again, look at the tectonic history of Europe or Southeast Asia) can be useful for getting more varied coastlines and more detailed topographies. Also, I elected not to worry too much about oceanic plates until about 250 million years ago, which is the age of the oldest oceanic crust on Earth, which saved me a huge amount of headache since that was by far the most frustrating part of doing the WP tutorial. Looking at reconstructions of Earth's tectonic plates it seems like mid-ocean ridges are frequently shifting and/or going extinct, so it's probably fine to give yourself a little bit of leeway there.

In general for figuring out tectonic history, I found Scotese's rules of thumb for plate tectonics to be a very useful guiding rule to complement the Worldbuilding Pasta tutorial. Specifically, keeping in mind that subduction zones are difficult to start and difficult to end was useful for not letting plate movement get out of control, as well as the reminder that mid-ocean ridges and subduction zones are most often parallel to each other and subduction is usefully orthogonal rather than oblique. It was also super useful to refer back to real-world tectonic history whenever I ran into conundrums- I would look for similar situations in Earth's past and either use that as a model or if I couldn't find anything similar, it was usually a hint that I got something wrong. GPlates actually has sample .rot files and shapefiles that go back through about 400 mya of tectonic history, which I was constantly referring to. If nothing else it's a reminder that all but the most recent plate tectonics are mostly guesswork so it's alright to let yourself off the hook if you're finding oceanic plates overlapping when they shouldn't or whatever. Apologies for the long-winded answer- I've been through this a couple times so far so I'm happy to chat more. I've been wondering if it's worth starting a Discord or something specifically for these bottom-up worldbuilding now that there are a number of us doing it, so that it's easier to share WIPs and tips and tricks for the process.

Also sharing the latest WIP, as I have to take a hiatus of a week or two thanks to work-related travel. Only about halfway through the second-largest continent (everything 750 meters above sea level and below), although I have a decent idea of where the proper mountains will go at this point. I've been debating whether to make that inland sea a true endorheic basin like the Caspian Sea or to have it draining through a deep canyon like I do now. The former is probably the more realistic choice, but the latter seems more fun from a worldbuilding standpoint- a river draining a huge inland sea isn't really something we have on Earth but it's cool to think about. It's also not completely far-fetched, as we have big gaps in continental volcanic arcs like the Columbia River Valley, and there's already some rifting in the center of the continent that could potentially travel down to the southern coast. Still debating though... perhaps I'll wait to see what the precipitation is like, as if it proves to be a huge desert perhaps an endorheic basin would make more sense.

Also note that I'm for the most part only doing the continents for now and saving islands for last- mostly because islands are the most fun to draw for me so it's nice to have something to look forward to

As always, critiques and comments are welcome!