RoboTank

Introduction

RoboTank is a mod for Factorio. It adds an entity called RoboTank that is like the stock tank except it will follow and fight with the player. It is possible to build a squad of RoboTanks that will stay together, attempting to maintain formation. This is meant as an alternative to the somewhat monotonous "turret creep" tactic.

Manual Installation

Copy the release zip file (RoboTank_X.Y.Z.zip) into the "mods" subfolder of the User Data Directory. Then start (or restart) Factorio. It should then appear in the Mods list available from the Factorio main menu, initially enabled.

Usage

First unlock the RoboTank technology. It requires Robotics, Tank, and Advanced Electronics 2 ("Blue Circuits") to be researched first.

Then create a RoboTank Transmitter and at least one RoboTank. Both are found in the Combat tab of the crafting menu (even though the normal tank is under Logistics).

Next, place a normal tank in the world. This will be the commander, and you will drive it manually. Near the commander, place your RoboTank(s). Where you put the RoboTanks in relation to the commander matters, as they will remember it as their formation position. Add fuel and ammo (bullets or cannon shells) to the RoboTanks.

Finally, put the RoboTank Transmitter into the inventory of the commander tank and start driving it. The RoboTanks will drive themselves to stay in formation and will automatically fire at enemy units and structures.

If you remove the transmitter from the commander, it ceases to be the commander. The RoboTanks will halt and wait for another commander (tank with transmitter in it) to come into existence.

Any type of vehicle, including modded vehicles, can act as the commander. However, in practice, it works best if the commander vehicle behaves similarly to the vanilla tank since the RoboTanks then have an easier time matching the commander's movements.

Features

RoboTanks can fire either bullets or cannon shells, depending on which is loaded into the ammo slot first. Once that category is exhausted, it will switch to the other category if available in an ammo slot. Otherwise it will try to take more ammo of the currently active category from the vehicle trunk, but will not switch ammo categories by taking from the trunk.

RoboTanks will try to avoid running into each other, with any other vehicle on the same force (set of allied players), and with the player.

RoboTanks that become "stuck" will try to escape by reversing a short distance and trying again.

You can get out of the commander tank and manually drive a wayward RoboTank to help it get where it is going--or, in an emergency, to escape from a battle gone horribly wrong!

Performance

The logic has been fairly heavily optimized for speed. On my test map with 40 tanks, RoboTank uses about 1.3ms per game tick when there is a commander, and about 20us per tick when there is no commander. It is fast enough to use on megabase maps.

In multiplayer usage, each player can have their own squad of tanks (but only one squad per player). Allied tank squads will avoid running into each other, so can be maneuvered in reasonably close proximity. However, while the mod is intended to be usable in PvP scenarios, that has not been tested.

Operation on multiple surfaces (planets)

RoboTanks on each surface (planet) operate independently of other surfaces. At any moment, there can only be one active commander vehicle per player, but when the player changes surfaces (including by using the map view), the active commander vehicle changes accordingly. Consequently, one can have a deployed squad on each surface, each of which will only self-drive when the commander is on the same surface.

Furthermore, remote driving works for both the commander vehicle and the RoboTanks. The RoboTanks even know to not run over the idle player character!

Construction and deconstruction by robots

RoboTanks can be put into a blueprint, and that will record the fuel, equipment grid contents, and logistic requests. This makes it possible to quickly deploy a squad with all gear.

RoboTanks cannot be marked for deconstruction by robots using a deconstruction planner; see forum post 2.0.12 Cannot deconstruct Tank with deconstruction planner. However, as noted in a reply on that post, it is possible to right-click-and-hold from the map view to mark them one at a time for deconstruction. In that case, the ammo that was loaded into the hidden turret entity spills out onto the ground, and the bots then pick up that ammo, which is a bit inelegant but it works and no ammo is lost in the process.

Firing cannon shells

The vanilla cannon shells do friendly fire damage. The RoboTank firing logic is oblivious to this, and will therefore regularly damage and destroy other squad members while trying to hit nearby enemies with cannon shells. You will almost certainly want to install Smart Cannon Shells alongside RoboTank if you use cannon shells in RoboTanks (which is recommended for dealing with high-evolution enemies).

However, if you decide to use vanilla shells rather than smart shells, you must enable the startup configuration setting "Impose cannon minimum range". This sets the minimum range to 5 units, and starts the projectile from that distance. Otherwise, the projectile (which is fired by the hidden turret entity) will hit the hull of the RoboTank that fired it. The main downside of this setting is it causes the muzzle flash to appear in