Seeds & Circuits
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Modding

Mod Kit

Make mods for Seeds & Circuits in Unity: write code, build prefabs, models and items in the editor, press Build.

Updated 11 Oct 2026

Mod Kit 1.0.0For game version 0.1.0 · 448.6 KB · updated 11 Oct 2026
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Make mods for Seeds & Circuits in Unity: write code, build prefabs, models and items in the editor, press Build.

Install

  1. Install Unity 6000.6 (the version the game uses) and make a new project (Universal 3D template, or any 3D one).
  2. Download the Mod Kit from the website and unzip it somewhere it can stay. Then Window ▸ Package Manager ▸ + ▸ Install package from disk... ▸ pick the kit folder's package.json. (Or add "com.seedsandcircuits.modkit": "file:<path to the kit folder>" to Packages/manifest.json.) The game's packages (Netcode, URP, Input System...) come along at the game's versions.
  3. The kit sets the project up once (linear colour, URP, .NET Standard 2.1); Seeds and Circuits ▸ Set Up Project runs it again.

Make a mod

  1. Seeds and Circuits ▸ New Mod...: name it. You get Assets/<Name>/ with:
    • <Name>.asset: the mod (id, name, side, items, recipes). Select it to build.
    • Code/: an assembly definition already pointing at the game's API, and a starter Mod class.
    • Content/: prefabs, models, textures, materials, sounds. Everything here goes into the mod.
  2. Write code in Code/ (see Documentation~/MAKING_MODS.md and MODS.md).
  3. Items and recipes: Create ▸ Seeds and Circuits ▸ Mod Item / Mod Recipe, then add them to the mod's lists. Tick only the fields you change; copy starts from a game item. Game ids: Documentation~/GameReference.md.
  4. Select the mod asset ▸ Build (or Build and Start Game). It goes straight into the game's Mods folder.

What's in the kit

Plugins/The game's API (the game's assemblies with the code taken out: names and types only). Mod code compiles against it; the game supplies the real code
Shaders/Stand-ins for the game's shaders. Give your materials these (e.g. SeedsAndCircuits/StylizedLit) to look like the game; the game puts its real shader on them when the mod loads. URP shaders work too
Editor/Build, New Mod, Mod Item / Recipe assets, Set Up Project
Documentation~/The modding guide, the API reference and the game's item ids, stations and shaders

Networked objects

Because Unity compiles your code, prefabs can carry your own NetworkBehaviours with RPCs and NetworkVariables. Register a prefab in OnLoad with RegisterNetworkPrefab("name", LoadContent<GameObject>("Assets/.../X.prefab")) (on every machine, so the mod's side must be both) and spawn it on the host with SpawnNetworkPrefab.

Rules

  • Same Unity version as the game, or bundles won't load.
  • Don't use UnityEditor in mod code (it isn't in the game).
  • Don't put Plugins/ DLLs in your mod: the game has the real ones.