Mapgen4

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What Mapgen4 is

Mapgen4 is a free procedural wilderness map generator from Red Blob Games. Choose a seed, paint mountains, valleys, and oceans, then let the simulation generate biomes and rivers using evaporation, wind, and rainfall. Sliders let you adjust simulation and visual settings, including rainfall and river flow. The terrain is rendered in 3D with a custom projection and outline intended to give maps a hand-drawn appearance. The page offers a high-resolution PNG download, and the maker says you may use your creations as you wish; credit is appreciated but not required. Mapgen4 runs on the web, and the source code is available for local browser use. The README provides build instructions using npm or pnpm and directions for running a local server. Mapgen4 and its helper libraries use the Apache v2 license, including for commercial projects. The maker describes the project as finished and mostly inactive. Rendering parameters are designed to look best around 25,000 Voronoi cells, although the underlying code can support more than one million. The page notes that it does not work on all platforms.

Who it suits

Mapgen4 suits people who want to create wilderness maps by painting terrain and tuning simulated weather settings. Its maker identifies independent, student, and hobbyist software developers as a main audience.

What it does well

Free to use on the web.
Paint mountains, valleys, and oceans from a chosen seed.
Adjust rainfall and river-flow settings.
Download high-resolution PNG maps.
Apache v2 licensing permits commercial projects.

What to know first

The maker describes the project as mostly inactive.
The page says it does not work on all platforms.
Rendering is designed to look best around 25,000 Voronoi cells.

Limits

Rendering parameters are designed to look best around 25,000 Voronoi cells, although the underlying code can support more than one million. The maker says the tool does not work on all platforms.

Getting started

Open the Mapgen4 website in a browser.
Choose a starting seed and paint mountains, valleys, and oceans.
Adjust simulation or style sliders, including rainfall and river flow.
Download the map as a high-resolution PNG.
For local use, build the source with npm or pnpm, run a local HTTP server, and open embed.html in a browser.

Verdict

Mapgen4 combines terrain painting with simulated biomes and rivers, and it offers both image export and source code for local use. Consider its platform caveat and mostly inactive status before relying on it for ongoing development.

Questions

Is Mapgen4 free?

Yes. Mapgen4 has a free plan, and no free trial is offered.

What platforms does Mapgen4 support?

It is available on the web and can be run locally in a browser using its source code.

Can I use maps I create commercially?

The maker says you may use created maps as you please; credit is appreciated but not required. Mapgen4 and its helper libraries are licensed under Apache v2 for commercial projects.

Who makes Mapgen4?

Red Blob Games identifies Amit Patel as its maker. Patel says he makes interactive visual explanations of math and algorithms.

Can I adjust how the map is generated?

Yes. You choose a seed, paint mountains, valleys, and oceans, and can adjust simulation and style sliders, including rainfall and river flow.

Can I run Mapgen4 locally?

Yes. The source code includes build instructions for npm or pnpm; the README says to run a local HTTP server and visit embed.html in a browser.

Facts from Mapgen4's own pages

Audience: Red Blob Games says its main audience is independent, student, and hobbyist software developers. · redblobgames.com, 2 Oct 2026
Code license: Mapgen4 and its helper libraries are licensed under Apache v2, and the maker says they can be used in commercial projects. · github.com, 2 Oct 2026
Controls: Sliders let you change the simulation and map style. · redblobgames.com, 3 Oct 2026
Download and local use: The repository provides the source code and instructions to build it with npm or pnpm and run it locally in a browser. · github.com, 2 Oct 2026
Export: The page offers a high resolution image download and says it does not work on all platforms. · redblobgames.com, 3 Oct 2026
Export and usage: The page offers a high-resolution image download and says users may do as they please with maps they create; credit is appreciated but not required. · redblobgames.com, 2 Oct 2026
Founded: 2018 · redblobgames.com, 28 Sept 2026
Limits: The README says the code can support over one million Voronoi cells, while rendering and other parameters are designed to look best around 25,000 cells. · github.com, 3 Oct 2026
Local use: The README gives build instructions and says to run a local HTTP server and visit embed.html in a browser. · github.com, 3 Oct 2026
Maker: Red Blob Games identifies Amit Patel as its maker and says he makes interactive visual explanations of math and algorithms. · redblobgames.com, 3 Oct 2026
Planned omissions: The maker lists drawing rivers, sphere output, natural resources, towns, forests, names, roads, and nations as features left for a future project. · github.com, 3 Oct 2026
Project status: The maker describes the project as finished and mostly inactive. · redblobgames.com, 3 Oct 2026
Purpose: Mapgen4 is a procedural wilderness map generator. · redblobgames.com, 3 Oct 2026
Security and compliance: The opened Mapgen4 page and repository do not state any security or compliance certifications. · redblobgames.com, 2 Oct 2026
Simulation: The generator simulates evaporation, wind, and rainfall to determine biomes and rivers. · redblobgames.com, 3 Oct 2026
Source code: The source is available on GitHub, and the README says Mapgen4 and the maker's helper libraries are licensed under Apache v2 for use in commercial projects. · github.com, 3 Oct 2026
Style: Its 3D rendering uses a custom projection and outline intended to give the map a hand-drawn look. · redblobgames.com, 3 Oct 2026
Support: The Mapgen4 page invites users to email the maker or comment on the page. · redblobgames.com, 3 Oct 2026
Terrain editing: You choose a starting seed and paint mountains, valleys, and oceans on the map. · redblobgames.com, 3 Oct 2026
Terrain style: It aims for a hand-drawn-inspired look, rendering terrain in 3D with a custom projection and outline. · redblobgames.com, 2 Oct 2026
Unbuilt features: The maker lists drawing rivers, sphere output, resources, towns, forests, names, roads, and nations as features that could be added in a future project. · github.com, 2 Oct 2026
Usage rights: The maker says anything created with the tool is yours to use as you please, and credit is appreciated but not required. · redblobgames.com, 3 Oct 2026

Where Mapgen4 stands on Freedom251

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