Draw an island. Watch it erode. Drop it into your world.

Hand-sculpting terrain and hand-painting its layers can eat weeks of production. Island Forge replaces that with shapes: draw land, peaks, ridges, rivers, paths, coves and coasts on a map, watch the island update shaded and in 3D as you drag, erode it in seconds, and apply it to a landscape with its ground textured, its grass planted and your PCG scatter regenerated. Change any shape later and apply again: placed actors ride the ground up or down, so what you built on the island stays standing.

It is a tool, not an asset pack: an editor window for Unreal Engine 5.8 with full C++ source, a Python and Blueprint library, and a CC0 starter set so your first island looks finished on day one.

Island Forge was built for Oathwake, our co-op survival RPG in development, to shape its islands. We liked it too much to keep it to ourselves.

AT A GLANCE

• Shape islands with handles on a map, or paint them freehand, not brushes on a landscape

• Ridges, rivers and paths that bend and branch; rivers cut gorges, paths keep to a grade

• Craters, calderas, mesas and terraced hills; a sunken crater makes a ring island round a lagoon

• Surprise me: a seeded island in six styles, from tropical to arctic

• Erosion in seconds: valleys, rain and settling, with presets

• A ground that paints itself: 8 layers, 8 grass types, 4 biomes, snow by sun and shade, damp ground by rivers

• Many islands on one shared World Partition landscape, meeting on one sea floor with no seams

• Gameplay masks, resource zones and suggested sites for your game's systems

• Baked maps for PCG, with example graphs for land, shore, reef and kelp

• JSON recipes that live happily in source control

• A CC0 starter set, an example island and an 88-page guide

HIGHLIGHTS

Shapes, not sculpting

Land, coves, peaks and ridges are shapes you drag on a map, blended smoothly, with coast warp so no outline looks like an ellipse. Or paint any of them freehand with a brush. Mark cliff and beach coasts, lay level ground for settlements and deep water for anchorages, and Island Forge builds the reef, shelf and seabed around them. Every shape stays editable.

Ridges, rivers and paths

Drag a mountain range from A to B, then right-click it: bend it, grow a spur, or split it to open a pass. Rivers are drawn the same way, with tributaries and a bed level at each point: they cut their channel, cross a ridge in a gorge and open into the sea, and their water is placed for you. Paths level their way across the ground, never steeper than their grade, cutting through humps and filling dips, and no grass grows on them.

Start from anywhere

Surprise me builds a seeded island in six styles (Tropical, Volcanic, Fjord, Atoll, Arctic, Temperate): a coast with coves, a landform, a river, a village with its landing and a path to a camp. Pick a size from 1.5 to 6 km, or sample an existing landscape and keep shaping.

A live workspace

The map and a 3D view side by side, rebuilding at 256, 512 or 1024 as you drag. Full builds go up to 8192.

Erosion in seconds

Valleys, rain and settling, multithreaded, with Gentle Hills, Tropical Volcanic, Rugged Mountains and Badlands presets. Flow, Wear, Deposits and Change views show what it did, and export as masks.

A ground that paints itself

The included auto-material lays up to 8 layers by height, slope, coast distance and sun: snow lies lower on a mountain's shaded side, and ground runs damp along rivers and valley floors. Height blending, hex tiling against repetition and side projection on cliffs. Up to 8 grass types with clumping and no-grass zones, four biomes, and a runtime virtual texture for big landscapes. Pack Surface Textures turns standard PBR maps into the material's packed pair.

One world, many islands

In a World Partition level, the islands share one landscape: the first island creates it in regions, each new island grows it, and every island fades into one sea floor, never meeting at a line. Islands are never written over each other, and Island Forge loads only the regions it needs.

Into the level

Create a landscape or apply to one you have. Against the Level shows what Apply would change before you commit. Placed actors move with their ground (boats and ocean actors can keep their height), and PCG regenerates on the new ground.

Built for gameplay

Walkable, buildable and spawn masks for AI and building systems. Resource zones for ore, wood, fishing or your own kinds, placed as tagged volumes. Suggest sites marks sheltered harbors, defensible hilltops and flat village spots where the island allows them.

Scatter that follows the land

Apply Ground bakes layer, terrain and gameplay maps and hands them to your PCG graphs, so scatter follows the valleys, the coast and the cliffs and keeps off paths and rivers. Example graphs cover the land, the shore (driftwood, shells, cliff-top trees), a warm reef and a cold kelp sea, with an underwater post process look.

Grass Push

Grass parts around your characters, bent on the GPU; the CPU cost is near zero.

Every island is a text file

Recipes are small JSON files that diff and merge in source control. Rebuild, apply and pack from Python or Editor Utility Blueprints, headless, for batch work and nightly builds. Heightmaps round-trip through external terrain tools.

WHAT'S INCLUDED

• The Island Forge editor window and its library, with full C++ source

• The ground auto-material and Island Forge's flowing river material

• A CC0 starter set (ambientCG, Poly Haven): 9 ground surfaces, card and scanned grass, 4 trees, shrubs and ground cover, 5 rocks, driftwood and shells, plus our own kelp, sea grass, coral and sea fans

• An example island map and example PCG graphs for land, shore, reef and kelp

• An 88-page user guide (PDF)
  
  Documentation Here

Our Tutorials will be on our YouTube channel here

The timelapse shown here is about an hour in real time to build the island.

ROADMAP

Island Forge is in active development.

Planned: waterfalls where a river meets a cliff, more island styles and stamps, and more scatter graph examples.

...Whatever else we cook up

SPECIFICATIONS & REQUIREMENTS

• Engine: Unreal Engine 5.8

• Platforms: Windows (Win64). Island Forge is an editor tool; the one runtime piece, the Grass Push component, ships in your Windows builds.

• Dependencies: the engine's Procedural Content Generation (PCG) plugin, enabled automatically. Nothing else.

• Code: full C++ source for both modules. No C++ needed to use it: everything is in the window, and a Python and Blueprint library covers scripting and batch builds.

• Documentation: an 88-page user guide (PDF, in the plugin) covering every tool, erosion, the ground material, World Partition, PCG scattering, the recipe format, scripting and troubleshooting.

• Third-party content: the starter set is CC0 (ambientCG, Poly Haven), credited in THIRD_PARTY.txt. The ground material's hex tiling is adapted from MIT-licensed sample code, notice included.