Getting Started

Welcome to Factory Builder!

Build automated production lines, smelt ores into plates, assemble components, and research upgrades. Your ultimate goal: produce Stars — the main scoring system that ranks your factory against others. Work your way up from Bronze to the legendary Prismatic Star!

First Steps

1 Place a Generator

Open the Build tool B select Generator, and place it. It auto-assigns the coal-burning recipe.

2 Place Miners

Add a Coal Miner (to fuel your Generator) and Iron/Copper Miners for resources. Set recipes via the sidebar after placing.

3 Connect with Belts

Use the Belt tool V to connect Miner outputs to machine inputs. Items flow in the arrow direction.

4 Set Recipes

Click a machine with the Select tool S to open its sidebar. Choose what it produces.

5 Add Depots

Place Depots in Collect mode at the end of production lines to gather items into your inventory.

6 Start Researching

Once you have research packs, build Labs and set a research target to unlock upgrades.

Machines

There are 6 machine types, each with a specific role in your factory. All machines occupy 1 tile.

Miner

No input 1 output Free

Extracts raw ores from the ground. Needs no input — just set a recipe and it produces resources from nothing. Connect its output to belts to move ores along.

Recipes: Mine Iron Ore Mine Copper Ore Mine Coal Mine Stone
Miners don't need power. Build them first to bootstrap your factory.

Smelter

1 input 1 output 5 MW

Refines raw ores into usable plates. Takes one input and produces one output. Requires power to operate.

Recipes: Smelt Iron Plate Smelt Copper Plate Smelt Stone Brick
Make sure you have a Generator running before placing Smelters, or they'll show "No Power".

Assembler

2 inputs 1 output 5 MW

Combines ingredients into intermediate products and research packs. Takes up to 2 inputs. Requires power.

Recipes: Iron Gear Copper Wire Circuit Red Research Pack Green Research Pack Blue Research Pack Bronze Star Silver Star Gold Star Prismatic Star
Plan belt layouts carefully — Assemblers often need two different input materials.

Research Lab

2 inputs No output 5 MW

Consumes research packs to complete upgrades. Set a research target, then feed the required pack types via belts.

Labs take 60s base per research cycle. The lab_speed upgrade makes them faster.

Generator

1 input No output +20 MW

Burns coal to produce power for your factory. Auto-assigns the "Burn Coal" recipe. Each generator produces 20 MW.

Recipes: Burn Coal
Build generators early — most machines need power. One generator supports ~4 machines.

Depot

1 input 1 output Free

Transfers items between belts and your inventory. In Collect mode, pulls items off belts into inventory. In Supply mode, pushes items from inventory onto belts.

Use Collect mode depots at the end of production lines to gather finished goods.

Items & Resources

Your factory processes 17 different items across 5 categories. Raw ores are mined, then refined and assembled into increasingly complex products — culminating in Stars, the main scoring items.

Raw Resources

Iron Ore
From: Mine Iron Ore
Used in: Smelt Iron Plate
Copper Ore
From: Mine Copper Ore
Used in: Smelt Copper Plate
Coal
From: Mine Coal
Used in: Burn Coal
Stone
From: Mine Stone
Used in: Smelt Stone Brick

Smelted Materials

Iron Plate
From: Smelt Iron Plate
Used in: Iron Gear, Circuit, Bronze Star
Copper Plate
From: Smelt Copper Plate
Used in: Copper Wire, Red Research Pack, Bronze Star
Stone Brick
From: Smelt Stone Brick
Used in: Green Research Pack

Intermediates

Iron Gear
From: Iron Gear
Used in: Red Research Pack, Blue Research Pack, Gold Star
Copper Wire
From: Copper Wire
Used in: Circuit
Circuit
From: Circuit
Used in: Green Research Pack, Blue Research Pack, Silver Star

Research Packs

Red Research Pack

The first research pack you can produce. Unlocks basic upgrades like miner and smelter speed. Made from Copper Plates and Iron Gears.

From: Red Research Pack
Green Research Pack

Mid-tier research pack. Unlocks assembler speed, belt throughput, and grid expansion. Requires Circuits and Stone Bricks.

From: Green Research Pack
Blue Research Pack

Advanced research pack. Unlocks lab speed, generator efficiency, and power output. Requires Circuits and Iron Gears.

From: Blue Research Pack
Used in: Prismatic Star

Stars

Bronze Star

The entry-level star. Assembled from basic plates — a good first scoring goal.

From: Bronze Star
Used in: Silver Star
Silver Star

Requires Bronze Stars and Circuits. A step up in factory complexity.

From: Silver Star
Used in: Gold Star
Gold Star

Requires Silver Stars and Iron Gears. Demands a well-oiled production line.

From: Gold Star
Used in: Prismatic Star
Prismatic Star

The ultimate prize. Requires Gold Stars and Blue Research Packs — only the most optimized factories can produce these.

From: Prismatic Star

Belts & Transport

Conveyor belts move items between machines. There are 4 belt types and 3 speed tiers.

Normal Belt 1 tile

Standard conveyor belt. Moves items in one direction.

Corner Belt 1 tile

90-degree turn. Press R to rotate through all 8 orientations (4 right turns + 4 left turns).

Splitter 4 tiles

Splits one input into three outputs. 1 input belt + 3 output belts in a T-shape.

Combiner 4 tiles

Merges three inputs into one output. 3 input belts + 1 output belt in a T-shape.

Belt Speed Tiers

TierSpeedNotes
Slow1 tile/sDefault tier
Normal2 tile/sDouble throughput
Fast4 tile/sMaximum throughput
Placement Tip: Use the Belt tool V and click-drag to place lines of belts. Press R to change direction. Corner belts auto-detect turns.

Power System

Most machines need power to operate. Generators burn coal to produce electricity.

How Power Works

  • Generators produce 20 MW each (affected by power_output upgrade: +15%/level)
  • Smelters, Assemblers, and Labs each consume 5 MW
  • Miners, Generators, and Depots require 0 MW
  • If power generation < consumption, powered machines show "No Power"
  • One coal lasts 180 seconds in a Generator (affected by generator_eff upgrade)

Power Planning

MachinePower DrawPer Generator (20 MW)
Smelter5 MW4 Smelters
Assembler5 MW4 Assemblers
Lab5 MW4 Labs
Miner0 MWUnlimited
Depot0 MWUnlimited
Always build coal miners and generators first. Without power, your factory grinds to a halt.

Research & Upgrades

Labs consume research packs to unlock powerful upgrades. Set a research target, then feed the required packs to your Labs.

How Research Works

  1. Assemble research packs (Red, Green, Blue) using Assemblers
  2. Feed packs to Labs via belts
  3. Set a Research Target in the upgrade panel
  4. Labs consume 1 of each required pack per cycle (60s base, affected by lab_speed)
  5. Once enough cycles complete, the upgrade level increases

Upgrade Reference

UpgradeCategoryEffectMax LevelResearch Cost
Miner Speedmachine+10% speed per level20 3/lvl
Smelter Speedmachine+10% speed per level20 3/lvl
Assembler Speedmachine+10% speed per level20 3/lvl
Lab Speedmachine+10% speed per level15 5/lvl
Generator Efficiencymachine+15% fuel efficiency per level10 5/lvl
Grid Expansionfactory+1 tile per side per level25 5/lvl 5/lvl
Belt Throughputfactory+25% belt speed per level10 5/lvl
Power Outputfactory+15% MW per generator per level10 5/lvl 5/lvl
Cost formula: round(baseCost × level^1.6) — costs scale up significantly at higher levels.

Stars & Scoring

Stars are the main scoring system in Factory Builder. Producing stars is the ultimate measure of your factory's success — collect them to climb the leaderboard and prove your optimization skills.

How Scoring Works

Stars are assembled in Assemblers like any other item, but they require expensive ingredients and long crafting times. Each tier builds on the previous — you need Bronze Stars to make Silver, Silver to make Gold, and Gold to make Prismatic. Collect Stars into your inventory via Depots to bank your score.

Star Tiers

Bronze Star Entry Level
Requires: 5 Iron Plate + 5 Copper Plate
200s craft time 10 MW
Silver Star Intermediate
Requires: 2 Bronze Star + 10 Circuit
400s craft time 10 MW
Gold Star Advanced
Requires: 3 Silver Star + 10 Iron Gear
600s craft time 15 MW
Prismatic Star Ultimate
Requires: 5 Gold Star + 3 Blue Research
1200s craft time 20 MW

Star Production Chain

Bronze Star
Iron Miner + Copper Miner Smelters Assembler (Bronze Star) Depot (Collect)
Prismatic Star (Full Chain)
Plates + Intermediates Bronze Silver Gold Prismatic Depot
Scoring Tips:
  • Stars are your factory's score — the more you collect, the higher you rank on the leaderboard
  • Higher-tier stars are worth more, but take significantly longer to produce
  • You need a well-established factory with research upgrades before tackling Gold and Prismatic stars
  • Don't forget to place Depots in Collect mode at the end of your star production lines to bank them into your inventory
  • Prismatic Stars require Blue Research Packs as an input — balance your research and star production carefully

Controls & Keybindings

Master these shortcuts to build faster.

Tool Modes

KeyToolDescription
SSelect toolClick machines to inspect
BBuild toolPlace machines on the grid
VBelt toolPlace conveyor belts
XDemolish toolRemove machines or belts
RRotateRotate placement direction
ESCBack to SelectCancel current tool

Camera Controls

InputAction
Middle Mouse DragPan camera
Right Mouse DragOrbit camera
Scroll WheelZoom in/out
Tools
S B V X
Actions
R ESC

Tips & Strategies

Early Game Strategy

1
Power First — Place a Coal Miner + Generator pair immediately. Belt coal from the miner to the generator.
2
Simple Chains — Start with Miner → Smelter → Depot chains for Iron and Copper plates. Stockpile basics before going complex.
3
Research Early — Get Red Research packs flowing ASAP. Miner speed and smelter speed upgrades compound quickly.

Production Chain Examples

Iron Plates
Miner (Iron) Smelter Depot (Collect)
Circuits
Iron Miner Smelter Assembler (Circuit) Assembler (Wire) Smelter Copper Miner
Red Research
Copper Miner → Smelter Assembler (Red Pack) Assembler (Gear) ← Smelter ← Iron Miner

Common Mistakes

× No coal supply to Generator

Generators need coal delivered via belt from a Miner with the "Mine Coal" recipe set.

× Forgetting to set recipes

Miners start idle. Click them and pick a recipe to begin production.

× Output buffer full

Machines stall at 100% when their output buffer (100 items) is full. Always connect outputs to belts and eventually to Depots.

× Belts pointing wrong direction

Check the arrow on belts. Press R to rotate before placing.

Optimization Tips

  • Use Splitters to fan one belt output to multiple machines
  • Use Combiners to merge multiple miners into one processing line
  • Upgrade belt speed to prevent belts from becoming bottlenecks
  • Expand your grid early — grid_expand gives you more building space
  • Balance miner-to-smelter ratios: one smelter takes 60s per plate vs. 30s per ore from a miner, so a 2:1 smelter-to-miner ratio keeps smelters fed