Geomorphology with Blender

Geomorphology is the science of the shape of mountains, rivers, islands, and other natural landmasses. Paleogeomorphology is the study of faults, erosion, and even tree rings which provide data on earthquakes which may have happened thousands of years ago.

The most fascinating aspect of geomorphology is the time-bracketing of events. Earthquakes can leave faulting which, relative to known processes like C₁₄ uptake and shoreline erosion, can result in windows of several centuries over which they may have occurred.

For a computational designer, it’s more traditional that mountains and terrains are generated purely from Perlin noise and Voronoi diagrams. However, while the process is remarkably efficient, they never seem to look quite right. Without the involvement of human hands, there is rarely any erosion or character on the terrain. This provides limited value in the context of a game, but what if we want to see a mountain with a history behind it? What if we want the land to tell a story, as real terrain often does?

Generated digital terrain formed in Blender and DLang
Sample terrain fragment after applying wind erosion, basic particulation, tree groves and fundamental water erosion.

An in-house project, currently going on here in the studio, uses a LAN-scoped web interface built in D, and a local server, to evolve land masses over time, from a baseline. Techniques like Söbel softening, very basic Voronoi diagrams, and Perlin distribution of density allow for erosive processes to iterate year by year. Since this is effectively a bake, time hasn’t been as much of an object; however, for 512×512 images it has been moving surprisingly fast. Depending on detail, we can currently run it in roughly two seconds; combined with rendering (including volumetrics) Eevee can have it ready in about fifteen seconds.

Currently, output is saved as a sequence of 8-bit gray scale PNG height maps and density maps, unfortunately that limits us to just 2⁸ or 256 values! An effort is being made to expand it to 16-bit gray scale PNG, bringing us to 2¹⁶ or 65,536 grades, or even 24-bit TIFF at 16,777,216 possible grades. However, most displays are only capable of 8-bit color, so not as many options remain. Most of these files are for scientific output, purely; as far as I know, no monitor is capable of accurately representing anything higher than 16-bit color, and most only 8-bit.

The FreeImage toolkit allows for, in theory, 32-bit gray scale or even double-precision floating point gray scale (64-bit), but that may do more harm to the project than good. After all, portability is important, and nothing meant for the human eye ever seems to go above 16-bits, so there is little support for this in most design software.

In theory, Blender (or any number of other 3D design programs) would truncate it at 16-bits anyway, and after a number is above the atomic unit of operation for a processor (typically 64 bits these days), there’s a noticeable slowdown. Time may be more valuable than precision here.

The remaining standing question is, what was our planet like for its baseline, before any tectonic or fluvial geomorphing? If we wanted to start from a clean-slate, with basic density voxels, would that give us a realistic result? It’s very hard to say at this point in history. We have a rough idea of how the planet formed, but between the stresses of heat and age, could any reliable evidence of that still exist? This period is generally known as the Hadean period, taking its root from “Hades”. The world was indeed very hell-like; it had an abundance of highly radioactive and short-lived elements, which have since decayed, and given that it was a mass of recently-pounded together space rocks, it was ridiculously hot. We’re talking about peak environmental erosion here, so assuming a perfect sphere with reasonable thermal radiance may still apply, whether the world ever looked like that or not.

One of the only remaining elemental minerals from that period is known as Hadean Zircon. Zircon, consisting of ZrSiO₄. It has a fusibility (melting-point) of 2550° C or 4620° F, which is ridiculously high. Its Mohs scale hardness value is around 7.6, a little short of topaz. It is also largely insoluble. Given the gemstone’s relative indestructibility, it seems reasonable that it would be one of the last surviving elements from the Hadean period; even still, only roughly 1% of zircons found globally are confirmed to be Hadean.

Hadean Zircon Fragment
Valley, John W., et al. “Hadean Age for a Post-magma-ocean Zircon Confirmed by Atom-probe Tomography.” Nature Geoscience 7.3 (2014): 219-223

The plan is to move from 2D-mapping to 3D-voxel data, and work from there.

Published by Michael Macha

I'm a game developer for both mobile and PC. My education is in physics, journalism, and neuroscience. Founder and CEO of Frontier Medicine Entertainment, located in the beautiful city of Santa Fe, New Mexico.

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