Apoapsis

Apoapsis is an interactive web-based star and planetary system generator inspired by Vector-Graphics' Periapsis.

Live demo: https://redreaper420.github.io/apoapsis/

Screenshots

Open/Close

Features

• Astrophysics-based seeded procedural generation of systems of main-sequence stars and planets (from tiny moons to brown dwarfs).
• Configurable generation parameters (star properties, planetary migration simulation regimes, etc.)
• Interactive 2D top-down visualization with time warp.
• Detailed body properties inspector.
• Scriptable generation filter.
• Saving & loading of systems and settings in JSON files.
• Total system report generation in HTML format.

Getting Started

Online

Just open the live demo.

Local / Self-hosting

1. Clone or download the repository (or a release).
2. Serve the files with any static HTTP server. Examples:

Python 3

python -m http.server 8000

Node.js (npx)

npx serve .

3. In a modern browser, open the URL leading to index.html at your server (i.e., http://localhost:8000 with Python server).

Tip

When hosting on your own server you can change the "Home" button destination by editing home_url.txt.

Quick Usage

Action	How
Generate a new system	Click ♻️ Generate at the top
Change seed / settings	Click ⚙️ at the top and navigate the opened settings overlay
Inspect a body	Click it in the view or use the navigation panel at the left
Toggle details rendering	Click buttons at the bottom (🌗 💡 🧲 ☁️ 🌐 🌱 🔆 🔄 🔍 🏷️ 💫 👁️)
Time warp	Click ▶️/⏸️ to toggle pause; drag the slider at the bottom to control simulation speed
Save / load system	Click 💾 / 📂 at the top
Export HTML report	Click 📄 at the top
Activate generation filters	1. Open the settings (⚙️) 2. Open the Filter tab 3. Select, paste, or type a script in the text box(es) (⚠️ only paste code you trust) 4. Click on Enable filter

Credits & License

Special thanks to @Vector-Graphics for inspiring this project through Periapsis and for allowing the use of original assets and concepts.

This project is licensed under the MIT License.

For third-party libraries, assets, and attributions, see THIRD_PARTY_LICENSES.md.