For Unity 6 and URP
Mythic Realm
Procedural open world and terrain generator for URP
An endless, seeded open world that streams around your player: eroded mountains, rivers from rain, real climate and biomes, forests, wildlife, weather and sound, and a one-click bake into Unity Terrain. Everything generated from code, ready for your game.
The Asset Store listing is on its way. Until then, the button opens an email to mythicrealm@tallgrassinnovation.com.
A whole world from a seed
Mythic Realm builds a whole world from a seed. Press Play and the land streams in around your player: eroded mountains and great ranges, gullies, mesas, cliffed coasts, glacial valleys and volcanoes, with rivers that come from rain and run downhill to the sea through lakes, deltas and waterfalls. A climate model places the biomes, from jungle to tundra, with snow lines and tree lines where they belong. Forests, rocks with ore, grass and wild flowers fill the land, and animals roam it.
The sky lives too: day and night, drifting clouds whose shadows cross the land, rain, snow and storms with lightning, wet and snowy ground, and the sound of the world (wind, birds, rain, rivers and the sea), all synthesised, with no audio files.
It is built to be a game's world, not a screenshot. Queries work from the first frame, events fire as chunks load and unload so you can place enemies, loot and buildings, a site finder gives the same camp spots every time, and players can mine rocks, fell trees and harvest animals for resources. Save games store only what the player changed, in a few hundred bytes, and each world profile pins its generator version, so a package update never reshapes a world you have shipped.
In the editor, bake any region up to 4 km into a real Unity Terrain, sculpt and paint it, and continue it seamlessly from its edge.
Everything is made from code and the seed: the same seed gives the same world on every machine, and nothing in the package is a fixed scene.
Key features
- Endless chunk streaming around the player, with distant land to the horizon (4 to 8 km) and level of detail for terrain, trees and grass
- Eroded terrain: great mountain ranges, gullies, ledges, mesas and buttes, sea cliffs, glacial valleys and fjords, volcanoes
- Rivers from rain that always run downhill: lakes, deltas, meanders, waterfalls, springs, frozen rivers
- A climate model (latitude, altitude, moisture) placing 11 biome types, with snow lines and tree lines
- Five world styles in one click: Temperate, Alpine, Archipelago, Desert canyons, Frozen north
- Forests of seven kinds of tree with cacti and tundra shrubs, rocks in several stones with 6 ores, bedrock outcrops, grass and wild flowers, all GPU-instanced
- Wildlife: rabbits, deer, boar, wolves, bears, antelope, camels, geese and eagles that wander, drink, flee and can be harvested
- Mining, felling and harvesting with tool tiers and resources for crafting
- Day and night, clouds with moving shadows, rain, snow, storms, wet and snowy ground, aerial haze and valley mist
- Synthesised ambient sound: no audio files
- Save games for the player's changes, and generator versions pinned per profile
- Gameplay API: WorldReady, chunk load and unload events, FindSpawnPoint, FindSites, height and biome queries
- Bake regions into Unity Terrain (trees, rocks, water, grass) and continue a sculpted terrain from its edge
- Low-poly flat-shaded water, and an optional faceted low-poly ground
- Quality tiers per Unity quality level, a built-in benchmark, and a setup check that fixes common problems
- Demo and Integration samples: fly around in seconds, or start from a first-person CharacterController
Compared with a typical terrain tool
| Feature | Mythic Realm | Typical terrain generator |
|---|---|---|
| Endless streaming world at runtime | Yes | Often editor-only, fixed size |
| Rivers that follow the land | Yes, from rain | Painted or spline-placed |
| Climate-driven biomes | Yes | Height or slope rules |
| Trees, rocks, grass | Built in, generated | Bring your own |
| Wildlife | 9 species, harvestable | No |
| Day and night, weather, sound | Built in | Separate products |
| Save games for player changes | Yes | No |
| Bake to Unity Terrain | Yes | Yes |
Requirements and platforms
- Unity: 6000.3.27f2 (6.3 LTS) or newer, through 6000.6 (6000.6.8f1 or newer). The security-patched releases.
- Render pipeline: Universal Render Pipeline (URP 17.3 or newer). Built-in and HDRP are not supported.
- Platforms: Windows verified (Direct3D 11 and 12, Mono and IL2CPP). macOS, Linux and Steam Deck expected to work, not verified. Mobile, WebGL, XR and consoles not supported.
- Performance (release player, RTX 3070, 1440p, Alpine world, view distance 8 / 16): Direct3D 11 256 / 245 fps, Direct3D 12 245 / 231 fps, no frame over 10 ms.
- Input: the Input System or the old Input Manager, no setup.
- Dependencies: URP and built-in modules only. No third-party assets needed.
- Content: code and shaders, two samples, documentation. No textures, models or audio files except one AI-generated wolf mesh (see the AI disclosure).
- Documentation: Getting started, a manual and an API reference, included in the package.
How it is made
Made with AI assistance. The code, including everything the package generates procedurally (terrain, rivers, biomes, plants, rocks, animals, sky, weather and sound), was written with the AI coding assistant Claude (Anthropic) and directed and reviewed by the author; no generative image or 3D models were used for it. One asset is AI-generated: the wolf's mesh, made with TRELLIS.2 (with DINOv3) from reference pictures generated with Grok from text prompts, then recoloured, rigged and animated by the package's code. A wolf built entirely from code can replace it (WorldFauna > Animal Models).
Start building your world
Install, press Play, and fly over a world made from a seed in under a minute.
Questions before you buy? Write to mythicrealm@tallgrassinnovation.com.