Advanced Electronics — Eco mod

A mod for Eco (Strange Loop Games) adding autonomous drones: craftable flying machines that a player slots into a Drone Dock and assigns to an area drawn on the map, which they then fly out to and work unattended.

Three drones ship:

• Survey Drone — prospects an assigned area and reports what is under it, per material, with quantity, location and depth.
• Mining Drone — digs out the plots a survey dock has already surveyed, fifteen layers down, and unloads what it breaks into storage you link to the dock. It mines as you: every removal is performed as the citizen who assigned the area, so settlement laws and private property refuse it exactly as they would refuse that citizen digging by hand.
• Farm Drone — levels, plows, sows and harvests an area, one crop per area, capped by a per-crop ceiling. It farms as you, through a Harvest Arm carrying the game's own farming tags, and it is the first drone here that places blocks rather than only removing them.

The dock's window grows a Survey, Mining or Farming tab depending on which drone is slotted, plus a standard Storage tab whose Take From / Put Into controls choose where a drone unloads.

Live-tested against Eco 0.14.1.1, which is also the version its reference assemblies are built from — EcoRefSha pins that exact tag. There is no Eco.ReferenceAssemblies package for 0.14 and the shipped server is a single-file bundle with its managed assemblies embedded, so the reference assemblies are built from a pinned source checkout instead — see scripts/gather-eco-refs.sh and EcoRefSha in the csproj.

Mod page: mod.io/g/eco/m/advanced-electronics — released builds are published there. This repository is the source; you only need to build anything if you are developing the mod. Server admins should take the release zip from mod.io and follow Installing a release.

Devlog: YouTube playlist — how and why the mod is being built.

⚠ Alpha — do not use on a world you care about

This mod is in alpha. Expect breaking changes between versions, including ones that are not migrated: an update can change how dock and drone state is stored, and older saved state may not survive it.

It is also known to leave orphaned objects in the world — drones that outlive their dock, or objects an update no longer recognises — which may need removing by hand with admin tools.

Run it on a test world, or a world where losing placed Drone Docks and their survey data is acceptable. Back up your save before updating.

Repository layout

Path	What it is
EcoServerMod/AdvancedElectronics/	Server half of the mod (.NET 10 class library) — WorldObjects, items, recipes, chat commands, drone logic. See EcoServerMod/README.md for build details.
EcoServerMod/AdvancedElectronics.Navigation/	Pure-C# navigation core (A* pathfinder, survey grid, lifecycle state machine) — unit-tested, zero Eco dependency, shipped alongside the mod DLL.
EcoServerMod/AdvancedElectronics.Navigation.Tests/	xUnit suite over the navigation core — no Eco dependency, so it runs from a bare clone with only a .NET SDK.
EcoServerMod/AdvancedElectronics.Spike/	Feasibility-spike reference project (kept deliberately as documentation of live-verified Eco API findings — not part of the shipped mod).
EcoServerMod/UserCode/	Whole-file .override copies of vanilla server files — Eco's escape hatch for attributes a mod assembly cannot extend. Installed by scripts/deploy-usercode-overrides.sh.
Repo root (Unity project)	Client half: Unity 6000.3.19f1 ModKit project that builds the asset bundle (dock/drone prefabs, item icon).
scripts/	Reference-assembly gathering, release packaging, the client/server name-match gate, UserCode override install.
AssetBundles/, dist/	Build output (git-ignored — rebuild locally, see step 2).
docs/	Plans, spike findings, manual test protocol, documented learnings (docs/solutions/).
CONCEPTS.md	Shared domain vocabulary (survey area, plot, finding, coverage, assignment).

Installing a release

For running the mod on a server — no build tools, no Unity, no clone required.

1. Download the release zip from the mod.io page.
2. Stop the Eco server.
3. Extract the zip and put the AdvancedElectronics folder into the server's Eco_Data/Server/Mods/, giving you Mods/AdvancedElectronics/:
   • AdvancedElectronics.dll — the mod
   • AdvancedElectronics.Navigation.dll — the navigation core the mod cannot load without
   • AdvancedElectronics.unity3d — the client asset bundle, which the server transfers to connecting players automatically (players install nothing by hand)
4. If updating, delete the old copy first — see the warning below.
5. Start the server and check the mods listing for Advanced Electronics.

Updating: remove the old copy from Mods/ entirely, don't just move it aside. Eco scans Mods/ recursively and keys asset bundles by filename, so a second copy of AdvancedElectronics.unity3d anywhere beneath Mods/ aborts startup with System.ArgumentException: An item with the same key has already been added. Key: AdvancedElectronics.unity3d. A folder you created and named Ignore, old or backup is still scanned — the name means nothing to the server. Move old copies out of Mods/ or delete them.

To uninstall, delete the Mods/AdvancedElectronics/ folder. Note that removing the mod discards any placed Drone Docks along with their survey areas and findings.

Setup after cloning

The server half needs no Unity and no ModKit, but it is not dependency-free. There are three tiers, and which one you need depends on what you are touching:

• EcoServerMod/AdvancedElectronics.Navigation and its test project build and test from a bare clone with nothing but a .NET SDK. They deliberately carry no Eco dependency at all.
• The mod itself (EcoServerMod/AdvancedElectronics) needs Eco's server reference assemblies. As noted at the top of this file, there is no Eco.ReferenceAssemblies package for 0.14, so run scripts/gather-eco-refs.sh against an Eco checkout and set EcoRefAssembliesDir in EcoServerMod/AdvancedElectronics/Local.props (git-ignored). The csproj errors with instructions if it is unset.
• The Unity client project needs the ModKit restore described below.

If you are only touching server C#, you can skip the Unity section entirely and go to Deploying to a server.

The Unity half does need a restore step. This repository contains only our own work. The Eco ModKit is distributed by Strange Loop Games from the play.eco website, behind an account that owns the game — there is no public download URL, and redistributing it here would route around that gate. So it is git-ignored rather than vendored, and a fresh clone will not open cleanly in Unity until you supply your own copy:

Path (git-ignored)	What it is
Assets/EcoModKit/	The ModKit itself — WorldObject, ModkitPrefabContainer, build tooling, template scene
Assets/EcoLibs/	Eco client utility libraries
Assets/Eco.Client.asmdef	The Eco client assembly definition. Scripts under Assets/ with no nearer asmdef — including ours — compile into it
Assets/Art/ThirdPartyPublic/	Vendored third-party libs (DOTween) the ModKit expects
Packages/com.strangeloopgames.eco-shared/	Precompiled Eco shared DLLs (embedded Unity package)
Packages/com.strangeloopgames.eco-modkit-deps/	ModKit's package dependencies (embedded Unity package)
Assets/TextMesh Pro/	Unity's TMP resources — the editor re-imports these on demand

You need to own Eco. Log in to play.eco with the Strange Loop Games account the game is registered to and download the ModKit for 0.14 from there; the step-by-step is Installing the ModKit on the Eco wiki. Note that their public EcoModKit repo holds example mods, not the kit — you cannot substitute it.

Packages/manifest.json and Packages/packages-lock.json are tracked here and already declare the two embedded packages, so dropping those folders into Packages/ is enough — do not re-add them through the Package Manager.

Why the copy has to be the official one

Unity references assets by the GUID recorded in each .meta file. Our tracked DroneDockObject.prefab references four GUIDs that live in the folders above. Import the official distribution (which carries the original .meta files) and they match. Copy the files loose, re-import them, or regenerate them any other way, and Unity mints fresh GUIDs — at which point the prefab silently loses its WorldObject component and the mod builds into a bundle that does nothing. There is no error message for this.

Check the restore worked before opening Unity:

grep guid Assets/EcoModKit/Scripts/WorldObject.cs.meta
# expected: guid: 22281bf2bb54279449ac8e3fbf199314

If that GUID differs, stop — your ModKit copy is not the one this repo's prefabs were authored against. Then open Assets/Art/AdvancedElectronics/Scenes/AdvancedElectronicsScene.unity and confirm the DroneDockObject prefab still shows a WorldObject component in the Inspector (not "Missing Script").

Deploying to a server for testing

0. Prerequisites

• An Eco 0.14 dedicated server you control. EcoRefVersion and EcoRefSha in the csproj must match the server's game build — see EcoServerMod/README.md > Version matching if yours differs.
• A .NET 10 SDK (dotnet --list-sdks shows a 10.x entry). No-admin user-local install instructions are in EcoServerMod/README.md > Building.
• Unity 6000.3.19f1 plus the Eco ModKit restored per Setup after cloning — only needed to (re)build the client asset bundle (step 2); skip both if you already have AdvancedElectronics.unity3d from a previous build.

1. Build and deploy the server DLLs

dotnet build EcoServerMod/AdvancedElectronics

Copy both DLLs from EcoServerMod/AdvancedElectronics/bin/Debug/net10.0/ into the server's Mods/ directory:

• AdvancedElectronics.dll — the mod
• AdvancedElectronics.Navigation.dll — the navigation core the mod cannot load without

Eco loads pre-compiled mods from Mods/ and any of its subdirectories, so dropping the DLLs loose in Mods/ is fine for a dev loop where you are overwriting them constantly. Releases use Mods/AdvancedElectronics/ instead — one folder to add or delete. Mods/UserCode/ is for source-code mods Eco compiles at runtime, not for a compiled-DLL mod like this one.

Or automate the copy: create EcoServerMod/AdvancedElectronics/Local.props (git-ignored) pointing at your server, and every build deploys both DLLs itself:

<Project>
  <PropertyGroup>
    <EcoModsDir>C:\path\to\EcoServer\Mods\AdvancedElectronics</EcoModsDir>
  </PropertyGroup>
</Project>

2. Build and deploy the client asset bundle

The bundle carries the dock/drone prefabs and the item icon. AssetBundles/ is git-ignored, so build it locally:

1. Open this repo's root folder in Unity 6000.3.19f1 and open Assets/Art/AdvancedElectronics/Scenes/AdvancedElectronicsScene.unity.
2. Menu Eco Tools > Mod Kit > Build Current Bundle (or "ModKit Tools…" to build all bundles). Output lands in AssetBundles/AdvancedElectronics.unity3d.
3. Copy AdvancedElectronics.unity3d next to the two DLLs on the server. Eco transfers mod assets to connecting clients — clients do not install anything by hand. (If objects appear as missing-model placeholders in-game, bundle placement is the first thing to re-check.)

Optional sanity gate before deploying: ./scripts/validate-name-match.sh confirms every server WorldObject/Item class has a matching-named client asset (the name match is how Eco links the two — a silent-failure seam if it drifts).

3. Restart the server and verify it loaded

Restart the Eco server and check the mods listing (server UI or console) for Advanced Electronics / the status line Advanced Electronics mod loaded.

4. Test in-game

Quick smoke test:

1. Craft a Drone Dock, a Survey Drone and a Mining Drone (all three at the Robotic Assembly Line) and place the dock.
2. Open the dock, Survey tab, click Manage Areas on Map. Draw one or more survey areas, name them, confirm. A dock holds at most ten.
3. Set View Position to the area you want, then click Assign Selected Area. The assignment line updates. Unassign Area stops the drone.
4. Insert the Survey Drone item into the dock's slot — a drone spawns beside the dock and heads for the assigned area. Removing the item destroys the drone and resets its state.
5. Watch the same tab for drone status and findings: the selector chooses which area you are reading, with per-material quantity, location and depth. Material Targets narrows the display; leave it empty to show everything.

Moving the selector only changes what you are looking at — it never reassigns a working drone. Assign and Unassign are the only controls that change what the drone does.

Findings persist with their area — reassigning the drone elsewhere and back does not lose them. Redrawing an area's geometry deliberately clears its findings (it is effectively a different area); renaming does not.

To mine what you surveyed, place a second dock and slot a Mining Drone. Its Mining tab lists the areas published by survey docks you own; pick one and press Assign Selected Area. The drone mines only plots that were actually surveyed, and skips ones it cannot reach. One pass takes fifteen layers — re-survey the pit floor to send it another fifteen deeper. Open that dock's Storage tab and use Take From / Put Into to choose where it unloads; with nothing linked it fills up and waits at the dock.

Diagnostics available in chat: /drone areas, /drone assignarea <id>, /drone survey, /drone filter [material], /drone status, /drone tags, /drone link [n], /drone animwatch, /drone farm (why an idle farm area is idle). Admin-only: /drone haltmining <on|off>, /drone orphans [destroy].

The full owner-run verification protocol (all flows and acceptance checks, with verdict tables to fill in) is docs/protocols/2026-07-survey-drone-manual-protocol.md.

Heads-up for the first live run: several Eco API behaviors cannot be verified offline (the reference assemblies ship with method bodies stripped) and are marked with ASSUMPTION comments in the server code — the manual protocol is what confirms them.

Dock and drone state does survive a restart, including a mining job resumed mid-shaft; that was verified live for 0.3.0. What can still go wrong across a restart is a drone left orphaned with no dock owning it — /drone orphans destroy removes those.

Server administration

Stopping every mining drone at once

/drone haltmining on     # every mining job on the server stops before its next removal
/drone haltmining off    # jobs resume

Admin-only, and server-wide by design — it is not a permission on any one dock. Mining drones delete terrain automatically and unattended, so a server owner needs one lever that reaches docks they have no access to, without hunting down their owners.

What it does and does not do:

• A running job stops before its next block removal, not mid-pack — nothing is left half-removed. The drone finishes travelling, declines to mine, and returns to its dock.
• The halt survives a restart. It stays on until someone turns it off.
• The dock's Mining tab reports "an administrator halted mining" as the stop reason, so the owner can see why their drone came home rather than filing it as a bug.
• Surveying is unaffected. Only mining halts.
• Nothing already mined is refunded or reverted, and hold contents are kept.

Everything else about the drones follows ordinary Eco authorization: access on the property and on the dock object. This command is the one exception, and it exists because a server owner's ability to stop automated excavation should not depend on who owns it.

Development

• Server code: EcoServerMod/README.md (projects, version pinning, building).
• Client assets: docs/guides/2026-07-survey-drone-unity-prefab-guide.md (keyboard-only prefab workflow, name-matching rules).
• Tests: dotnet test EcoServerMod/AdvancedElectronics.Navigation.Tests (260 tests over the pure navigation/survey/mining/lifecycle core — no Eco dependency, so they run anywhere).
• Documented learnings: docs/solutions/ — solutions to past problems, organized by category with YAML frontmatter.
• Shared vocabulary: CONCEPTS.md.

Cutting a release

scripts/package-release.sh [--version X.Y.Z] builds the Release DLLs, runs the tests, and assembles dist/AdvancedElectronics-<version>-eco<game>.zip in the layout Installing a release describes — ready to upload to mod.io.

Rebuild the asset bundle in Unity first. The script does not build it (that needs the Editor) but it does refuse to package one that is older than anything under Assets/Art, because the bundle carries the prefabs, materials and animator controllers — a stale bundle ships client assets that silently disagree with the DLLs. If a git operation has rewritten source mtimes and you know the bundle is current, --force overrides.

Known limitations

• Drones fly through trees, stockpiles and other placed objects. They route around whatever exists when they plan a trip and pass straight through anything built afterwards. Nothing is damaged or moved — a visual fault only.
• A drone starts travelling before its take-off animation finishes. The server times these by counting animation frames rather than being told when a clip ends, so the two drift. Cosmetic.
• The Drone Dock is a placeholder cube, drawn about a metre above the volume it occupies, with no ghost outline while you hold it. It places and works normally. Item and skill icons are flat-colour placeholders too.
• Mining is not reversible from inside the mod. A worked plot is left as an open pit with a 3×3 mouth, and there is no fence around it. Drones cannot place blocks, so there is no backfilling and no safety rim.
• A drone can be left orphaned across a restart — alive with no dock owning it. Admins clear these with /drone orphans and /drone orphans destroy.
• The Harvest Drone exists in the source but is not craftable, and the Advanced Electronics Assembly is excluded from the build.

License

Copyright (C) 2026 Iuri Guilherme

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with this program.  If not, see <https://www.gnu.org/licenses/>.

The full LGPL text is in LICENSE.

Attribution

The HRVSTR-01 drone -- its mesh, textures, rig and animation clips, under Assets/Art/AdvancedElectronics/Sprites/HRVSTR/ -- was created by Phlo123 and is licensed under the Creative Commons Attribution-ShareAlike 4.0 International license. The full text of that license is in LICENSE-ART.

Third Party

Eco, the Eco ModKit and their assets remain the property of Strange Loop Games. They are not redistributed here -- they are account-gated downloads for owners of the game, so mirroring them would route around that gate; see Setup after cloning for the paths involved and how to supply your own copy. The grant above covers this project's own work only. It does not extend to anything of theirs, and it does not give you rights to the game or the ModKit.