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Main Assembly

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Main Assembly
Main Assembly cover
Bad Yolk Games
Unreal Engine 4[Note 1]
Release dates
Windows January 26, 2021
Monetization One-time game purchase
Microtransactions None
Modes Singleplayer, Multiplayer
Pacing Real-time
Perspectives Free-roaming camera, Third-person
Controls Direct control, Menu-based
Genres Simulation, Vehicle combat, Vehicle simulator
Art styles Stylized
Themes Sci-fi
Main Assembly on IGDB
Main Assembly on MobyGames

Main Assembly is a 1-4 player vehicle simulation utilizing pre-made and user-built vehicles developed by Bad Yolk Games and published by Team17.

Closed betas was held from 16 December 2019 to 24 January 2020[2][3] and 14 February 2020 to 28 February 2020.[4] An open beta was held from 26 March 2020 to 5 May 2020.[5][6] From 28 May 2020 to 8 June 2020, the first 55,000 entrants in a PCGamer giveaway had access to a special closed beta.[7][8]

The game was formally released into early access on 11 June 2020 and left it on 26 January 2021.[9][10]

The game released its first post-launch patch, version 1.1, into public beta on 11 August 2021, which added quality-of-life features and fixed several issues, such as pressing the A button on an XInput controller resulting in text chat being opened.[11] However, this update, as of 12 April 2022, has not left public beta.

General information

Official Discord server
Publisher Discord server
Steam Community Discussions


All versions require Steam DRM.

Essential improvements

Skip intro videos

Delete or rename files[12]
  1. Navigate to <path-to-game>\RoboBuild\Content\Movies
  2. Delete or rename BYGLogo.mp4 and Team17_Ident_2018_01_MainAssembly_Audio.mp4.

v1.1 beta patch

The final official patch by the developers, the v1.1 beta patch adds a number of quality-of-life features as well as fixes some bugs (see Issues fixed for notable bugs).
Switch to experimental branch[11]
  1. Follow the official instructions.

Game data

Configuration file(s) location

System Location
Windows %LOCALAPPDATA%\RoboBuild\Config\WindowsNoEditor
Steam Play (Linux) <Steam-folder>/steamapps/compatdata/1078920/pfx/[Note 2]

Save game data location

System Location
Windows %LOCALAPPDATA%\RoboBuild\Saved
Steam Play (Linux) <Steam-folder>/steamapps/compatdata/1078920/pfx/[Note 2]

Save game cloud syncing

System Native Notes
Steam Cloud


Game settings.
Game settings.
Graphics settings.
Graphics settings.

The game engine may allow for manual configuration of the game via its variables. See the Unreal Engine 4 page for more details.


Control bindings.
Control bindings.

Keyboard and mouse State Notes
Certain actions, such as moving the player's drone up and down, cannot be remapped.
Mouse acceleration
Mouse sensitivity
Driving and drone sensitivity can be set individually.
Mouse input in menus
Mouse Y-axis inversion
Called Invert Mouse.
Controller support
Full controller support
Controller remapping
See the glossary page for potential workarounds.
Controller sensitivity
Controller Y-axis inversion
Called Invert Drive Camera.
Controller types
XInput-compatible controllers
Xbox button prompts
Impulse Trigger vibration
DualShock 4 controllers
DualShock button prompts
Light bar support
Connection modes unknown
Generic/other controllers
See the glossary page for potential workarounds.
Additional information
Controller hotplugging
Haptic feedback
Simultaneous controller+KB/M
Steam Input
Steam Input API support
Hook input (legacy mode)
Official controller preset(s)
Steam Controller button prompts
Cursor detection


Audio settings.
Audio settings.

Audio feature State Notes
Separate volume controls
Music, SFX, voice.
Surround sound
Closed captions
Mute on focus lost
Royalty free audio


Language UI Audio Sub Notes
Simplified Chinese
Traditional Chinese
Brazilian Portuguese


Multiplayer types

Type Native Players Notes
LAN play
Online play
4 Co-op, Versus

Connection types

Type Native Notes

Issues unresolved

The developer maintains a list of known issues here.

Issues fixed

Game closes to main menu when Internet connection is lost when in single-player or multiplayer host

Fixed in the v1.1 beta patch.[15]

'A' button on XInput controller always opens text chat

Fixed in the v1.1 beta patch.[16]

Other information


Technical specs Supported Notes
Direct3D 11, 12
Shader Model support 5
Executable 32-bit 64-bit Notes


Middleware Notes
Physics PhysX [17]

System requirements

Minimum Recommended
Operating system (OS) 7
Processor (CPU) Intel Core i5-3570
System memory (RAM) 4 GB
Hard disk drive (HDD) 3 GB
Video card (GPU) Nvidia GeForce GTX 770
A 64-bit operating system is required.


  1. Unreal Engine 4 engine build: 4.24.2[1]
  2. 2.0 2.1 File/folder structure within this directory reflects the path(s) listed for Windows and/or Steam game data (use Wine regedit to access Windows registry paths). Games with Steam Cloud support may store data in ~/.steam/steam/userdata/<user-id>/1078920/ in addition to or instead of this directory. The app ID (1078920) may differ in some cases. Treat backslashes as forward slashes. See the glossary page for details.


  1. Verified by User:Expack3 on 2022-04-12
  2. Steam Community Announcement - Closed Beta is Live - last accessed on 2022-04-12
  3. Steam Community Announcement - Devblog #2 - New Programming Features! - last accessed on 2022-04-12
    "Before we get stuck in though, the closed beta is over and we've been busy going through all of your feedback, taking notes and discussing what we've learned from it. We just want to say a big THANK YOU to everyone who participated!"
  4. Steam Community Announcement - Main Assembly Beta & Early Access Release Date Trailer! - last accessed on 2022-04-12
    "A Main Assembly beta is on the way! It will be live from 2pm GMT on February 14th and will finish at 2pm GMT on February 28th!"
  5. Steam Community Announcement - Main Assembly Open Beta - last accessed on 2022-04-12
  6. Steam Community Announcement - End of Open Beta - Thank you to all Inventors! - last accessed on 2022-04-12
  7. Steam Community Announcement - PC Gamer Beta and Gaming PC Giveaway - Live Now! - last accessed on 2022-04-12
  8. PCGamer - Snag a free Main Assembly beta key and get a chance to win a Reign SENTRY MKII gaming PC - last accessed on 2022-04-12
    "We've secured 55,000 Steam keys for the beta of Main Assembly, Bad Yolk Games and Team17's robot building sim. Rather than attempt to fashion them into a fearsome robot made entirely of ASCII, we've decided to pass them along to you."
  9. Steam Community Announcement - Main Assembly Early Access Launch - last accessed on 2022-04-12
  10. Steam Community Announcement - Main Assembly 1.0 is now available! - last accessed on 2022-04-12
  11. 11.0 11.1 Steam Community Announcement - Main Assembly 1.1 Patch - now live for Beta testing! - last accessed on 2022-04-12
  12. Verified by User:Expack3 on 2022-04-12
  13. YouTube - Main Assembly - Gameplay (PC/UHD) - last accessed on 2022-04-12
  14. 14.0 14.1 Verified by User:Expack3 on 2022-04-12
    Tested using Universal Unreal Engine 4 Unlocker v3.0.19.
  15. Steam Community Announcement - Main Assembly 1.1 Patch - now live for Beta testing! - last accessed on 2022-04-12
    "Connection Issues will no longer throw you into the Main Menu if you're in Single Player or the Host of a game"
  16. Steam Community Announcement - Main Assembly 1.1 Patch - now live for Beta testing! - last accessed on 2022-04-12
    "Xbox A-button no longer opens the chat"
  17. Verified by User:Expack3 on 2022-04-12
    While the official FAQ states the game uses Bullet Physics, no DLL exists in the game files which correspond to Bullet Physics; instead, only PhysX DLLs could be found.