Sun 28 Apr 2024 ↻ Wed 4 Feb 2026 (older version originally published at wordpress.com)

hcks.eu /proj /earthen

Earthen: Dirt Simulator is a free open-source digital game project about solarpunk gardening and soil life, designed by Vrtxd. Below you can find a description of the project. For a quick visual vibe of the idea, scroll to the end of this page for some concept art.

#Earthen #EarthenGame #EarthenDirtSim #DirtSim #SoilLifeSim #GardenSim

Concepting Earthen originally started in early 2021 as a primitive open-world wilderness survival sandbox game, inspired by Primitive Technology by John Plant. When attempting to design a plausible plant growing system for the game, I realized that even though I had farmed numerous virtual vegetables in many games before, I still did not actually understand how a real one is grown. The game concept then gradually evolved into a game about gardening as I learned more about biology, soils and chemistry.

The game concept is essentially a voxel-based physics simulation engine that models cubic volumes of one litre (10×10×10 cm), and each of these voxels contains simplified abstractions of various natural biogeochemical phenomena:

These mechanics allow the engine to flexibly represent various materials that can be broken back down to their constituents, for example:

These voxels then interact with the surrounding voxels to produce dynamic environmental phenomena such as:

Finally, the cubic voxel world is populated with live and dead organisms, such as animals, fungi and plants, as well as technical constructions and player characters, that all interact with the dynamic voxel environment and each other. Animal droppings and dead organisms decompose over time and convert into environmental voxel data, while seeds and spores stored in the voxel data may spawn new organisms to the world.

Since 2024, I have been learning the Godot game engine and trying to build a prototype of Earthen with it. As of 2026, this implementation is still in its very early, nonplayable stages. You can find the development logs here and the source code at GitLab.

Concept art

Pixel art style image. Title: Voxel Palette 3.0. License plate: CC BY vrtxd 2024. Tiny 8×8-pixel cubes arranged in a color spectrum grid. Bright at the top, dark at the bottom. Colors from left to right: grey, red, orange, yellow, green, teal, blue, purple. Text: 11 shades of 7 primary colors in 3 saturations + 11 shades of grey + black + white = total 244 colors tip: dither for even more colors! green + teal = mint teal + blue = azure blue + purple = violet purple + red = rose red + orange = scarlet orange + yellow = amber yellow + green = chartreuse Pixel art style image, 3 data tables. White/grey text, black outlines, grey table borders, dark grey background. Grey particles, grey/red/blue charges. License plate: vrtxd 2025, public domain mark. Title: Subatomic particles Table 1: elementary particles Column 1: gen I fermions - up quark (u): pos. quark, charge +⅔ - down quark (d): neg. quark, charge –⅓ - electron (e): neg. lepton, charge –1 - electron neutrino (ve): charge 0 Column 2: gen II fermions - charm quark (c): pos. quark, charge +⅔ - strange quark (s): neg. quark, charge –⅓ - muon (μ): neg. lepton, charge –1 - muon neutrino (vμ): charge 0 column 3: gen III fermions - top quark (t): pos. quark, charge +⅔ - bottom quark (b): neg. quark, charge –⅓ - tauon (τ): neg. lepton, charge –1 - tauon neutrino (vτ): charge 0 column 4: gauge bosons - gluon (g): charge 0 - photon (p): charge 0 - Z boson (Z): charge 0 - W boson (W): charge +1 / –1 column 5: scalar bosons - Higgs boson (H): charge 0 Table 2: nucleons - composite particles - nucleons - p⁺ proton: 2 up quarks + 1 down quark, charge +1 - n⁰ neutron: 1 up quark + 2 down quarks, charge 0 Table 3: example atoms from particles, header row: particles, atom, name - p⁺ = ¹₁H₁⁺ = H⁺ hydrogen-1 cation (proton) - p⁺ e⁻ = ¹₁H₁⁰ = H hydrogen-1 (protium) - p⁺ e⁻ e⁻ = ¹₁H₁⁻ = H⁻ hydrogen-1 anion (protide) - p⁺ n⁰ e⁻ = ²₁H₁⁰ = ²H hydrogen-2 (deuterium) - p⁺ n⁰ n⁰ e⁻ = ³₁H₁⁰ = ³H hydrogen-3 (tririum) ☢ - p⁺ p⁺ n⁰ e⁻ e⁻ = ³₂He₁⁰ = ³He helium-3 - p⁺ p⁺ n⁰ n⁰ e⁻ = ⁴₂He₁⁺ = ⁴He helium-4 cation Pixel art style text featuring color-coded chemical substances and subatomic particles. Atoms are particles made of p⁺ protons and n⁰ neutrons at the atomic nucleus and e⁻ electrons at the atomic orbital. p⁺ protons define the substance's element, n⁰ neutrons define the substance's isotopes, and e⁻ electrons define the substance's electric charge. Here are some various H hydrogen atoms illustrated: (illustrations of the first eight atoms and a table) p⁺: ¹H⁺ proton p⁺ e⁻: ¹H protium p⁺ e⁻ e⁻: ¹H⁻ protide p⁺ n⁰: ²H⁺ deuteron p⁺ n⁰ e⁻: ²H deuterium p⁺ n⁰ e⁻ e⁻: ²H⁻ deuteride p⁺ n⁰ n⁰: ³H⁺ triton ☢ p⁺ n⁰ n⁰ e⁻: ³H tritium ☢ p⁺ n⁰ n⁰ e⁻ e⁻: ³H⁻ tritide ☢ hydron cations: proton, deuteron, triton uncharged atoms: protium, deuterium, tritium hydride anions: protide, deuteride, tritide Average H hydrogen on Earth is ca. 99.9855 % ¹H and 0.0145 % ²H. CC BY vrtxd 2023 Pixel art style image. Periodic table of chemical elements, dark mode, compact. Title text: Periodic Table of Elements Text paragraph: 🟩 Elements are groups of similar ⚛️ atoms with the same number of p⁺ protons. These elements are listed on the ⬜ periodic table. The periodic table of the elements in pixel art style, color-coded by blocks (s: orange, p: red, d: blue, f: green). Pixel art style image. Periodic table of chemical elements, dark mode. White text on dark teal background. Title text: Elements & The Periodic Table 🟩 Elements are groups of similar ⚛️ atoms with the same number of p⁺ protons.These elements are listed on the ⬜ periodic table. The periodic table of the elements in pixel art style, color-coded by blocks (s: orange, p: red, d: blue, f: green), with H hydrogen highlighted/selected and shown magnified with details: ₁H hydrogen 1.008 CC BY vrtxd 2023 Pixel art style image. Periodic table of chemical elements, light mode. Black text on light beige background. Title text: Elements & The Periodic Table 🟩 Elements are groups of similar ⚛️ atoms with the same number of p⁺ protons.These elements are listed on the ⬜ periodic table. The periodic table of the elements in pixel art style, color-coded by blocks (s: orange, p: red, d: blue, f: green), with H hydrogen highlighted/selected and shown magnified with details: ₁H hydrogen 1.008 CC BY vrtxd 2023 Pixel art style image. Periodic table of elements, light mode, larger text for legibility. The periodic table of chemical elements, in pixel art style, on a beige background. Table color-coded by blocks: orange s-block, red p-block, blue d-block, green f-block. Title: Periodic Table of Elements. CC BY vrtxd 2024. Pixel art style image. Periodic table of elements, light mode, with proton numbers. CC BY vrtxd 2024. Pixel art style infographic image. Black text on white background. States of Matter #1: Overview Physical matter exists in various different forms called states of matter. The classical four fundamental states are solid, liquid, gas, and plasma. Here are some examples of these states found in nature: Example: solids ice, snow, rocks, coal, dirt, wood, biomass, dust, glass, plastic, bricks Example: liquids rainwater, clouds, oil, magma, honeydew, milk, blood, mercury Example: gases water vapor, air, oxygen, ozone, nitrogen, argon, carbon dioxide, natural gas, ammonia, helium Example: plasma most flames, lightning, electric arcs, stars, stellar coronas, solar winds, auroras, nebulas, comet trails CC BY vrtxd 2024 Pixel art style infographic image. Black text on white background. States of Matter #2: Properties The state of matter affects the shape, the volume and the particles of the substance. (Images of cylindrical containers with: solid prism standing in the container, liquid at the bottom of the container, semi-transparent gas filling the container, glowing plasma filling the container. Closeup images of particle structures: solid particles close together in an arranged grid, liquid particles close together settled to the bottom, gas particles far apart floating around, glowing plasma particles far apart floating around.) (Table with columns for solid, liquid, gas and plasma.) Solid: fixed shape & particles. Liquid, gas & plasma: varying shape, particles move freely. Solid & liquid: fixed volume, particles close together. Gas & plasma: varying volume, particles far apart. Solid, liquid & gas: atoms, molecules. Plasma: ions, electrons. CC BY vrtxd 2024 Pixel art style infographic image. Black text on white background. States of Matter #3: Phase Changes When matter changes from one state to another, it is called a phase change, or a phase transition. These phase changes most typically happen when either temperature or pressure changes. (Infographic of phase changes. Solid, liquid, gas and plasma in cylindrical ontainers.) solid → melt → liquid solid → sublime → gas liquid → freeze → solid liquid → vaporize → gas gas → condense → liquid gas → deposit → plasma plasma → recombine → gas temperature → cool → colder temperature → heat → hotter pressure → increase → more pressure pressure → decrease → less pressure Example: H₂O water ice melts to liquid water; water boils (vaporizes) to water vapor; water vapor condenses to liquid water; liquid water freezes to ice. CC BY vrtxd 2024 Pixel art style image. What is in the air? typical dry air: ca. · 78.0795 % nitrogen N₂ · 20.9420 % oxygen O₂ · 0.9335 % argon Ar trace gases: · 0.0420 % carbon dioxide CO₂ · 0.0018 % neon Ne · 0.0005 % helium He · 0.0002 % methane CH₄ · 0.0005 % others Burning fossil fuels & biomass, producing cement & deforestation increases CO₂. 💔 Pixel art style image. Dry air typically contains: 78.0795 % N₂ nitrogen 20.9420 % O₂ oxygen 0.9335 % Ar argon 0.0420 % CO₂ carbon dioxide 0.0018 % Ne neon 0.0005 % He helium 0.0002 % CH₄ methane total 0.0005 % * other trace gases Pixel art style infographic image. Water Vapor Water vapor is an invisible, airborne form of H₂O water that is in the gaseous state. 2 × H hydrogen + 1 × O oxygen = H-O-H = H₂O water H hydrogen and O oxygen in the periodic table: (periodic table) ¹H: period (row) 1, group (column) 1, s-block ⁸O: period (row) 2, group (column) 16, p-block Water vapor is created usually when liquid water evaporates or boils, or less commonly when solid ice sublimes. When water vapor condenses to liquid water, it forms droplets that create dew, clouds, fog, mist, drizzle and rain in the air. When water vapor deposits to solid ice, it forms crystals that create ice clouds, ice fog, frost, snow, ice pellets, graupel and hail in the air. CC BY vrtxd 2024 Water phase diagram (alt text in progress) Pixel art style text featuring color-coded chemical compounds. Average seawater contains ca. 96.5 % H₂O pure water and 3.5 % salts, which consist of ca. - 55 % Cl⁻ chloride - 31 % Na⁺ sodium - 7.7 % SO₄²⁻ sulfate - 3.7 % Mg²⁺ magnesium - 1.2 % Ca²⁺ calcium - 1.1 % K⁺ potassium - .41 % HCO₃⁻ bicarbonate - .19 % Br⁻ bromide - .08 % BO₃³⁻ borate - .04 % Sr⁺ strontium - <.01 % other trace components pH ↑ up: ⁺ cation & OH⁻ hydroxide form alkali salts. pH ↓ down: ⁻ anion & H⁺ hydron form acid salts. some salts: - Na⁺ sodium & Cl⁻ chloride: NaCl table salt - Na₂²⁺ sodium & SO₄²⁻ sulfate: Na₂SO₄ sodium sulfate - Ca²⁺ calcium & Cl₂²⁻ chloride: CaCl₂ calcium chloride - K⁺ potassium & Cl⁻ chloride: KCl potassium salt - Na⁺ sodium & HCO₃⁻ bicarbonate: NaHCO₃ baking soda CC BY vrtxd 2023 Pixel art style infographic image. inputs: - H₂O water - CO₂ carbon dioxide - ☀️ sunlight → oxygenic photosynthesis → outputs: - oxygen O₂ - CₓHₓOₓ carbohydrates examples: - simple sugars (monosaccharides): glucose, fructose, galactose etc. (C₆H₁₂O₆) - starch, cellulose (C₆H₁₀O₅)ₓ+(H₂O) some simple sugars: C₆H₁₂O₆ glucose (illustrated molecular structure of glucose) C₆H₁₂O₆ fructose (illustrated molecular structure of fructose) note: same formula, different structure CC BY vrtxd 2024