I decided to create this guide because there was no tutorial in French on the installation of the mod Nitrox that allows to play in multiplayer Subnautica, available at this address: https://github.com/SubnauticaNitrox/ Nitrox /
You can also see what has already been done here: https://trello.com/b/ftPCv2DL/subnautica-nitrox

I want to clarify that I am not the creator of this mod, it is under development and that bugs can exist.

This is not an official mod, the creators of Subnautica are not at the origin of this mod.

This mod allows to play in multiplayer on Subnautica, pending a possible official update for multiplayer.

/! \ This mod modifies the internal core of Subnautica, so the method is not risky for the game, but in case of problems, a complete reinstallation of the game removes the mod.
In case of update of the game, I do not know if the mod is deleted or not, but if in doubt, it is better to put it on Subnautica. /! \

Discord FR-EN : https://discord.gg/4vhWnQ7

An installer is now out : https://www.nexusmods.com/subnautica/mods/159?tab=description

You just need to create an account (for free) and choose manual download of the mod, extract the installer from the .rar and launch it, then change the path with the path of Subnautica and finish the installation.

After that, the NitroxServer is located on the folder of Subnautica in SubServer, at this point you can do the III without the I and the II !

Enjoy !

-Download:

Visual Studio: https://www.visualstudio.com/en/thank-you-downloading-visual-studio/?sku=Professional&rel=15&rr=https%3A%2F%2Fwww.youtube.com%2F

Git Bash: https://git-scm.com/download/win

Notepad ++: https://notepad-plus-plus.org/repository/7.x/7.5.4/npp.7.5.4.Installer.exe

dnSpy: https://github.com/0xd4d/dnSpy/releases

-Install these programs. For Visual Studio, a window will appear to ask you to install "components", install the component for .Net (about 3Go ~ 3,5Go size)

-Start Git Bash

-Enter the window that appears: "git clone --recurse-submodules https://github.com/SubnauticaNitrox/Nitrox.git Documents / Nitrox"

-Go to "Documents" then "Nitrox"

-Start Visual Studio in Administrator
(Attention, Subnautica must be on the C: base disk, in C: \ Program Files (x86) \ Steam \ steamapps \ common \ Subnautica, if it is not, a modification is to do, see II)

-In Visual Studio File-> Open Project and go to the window that opens the file Nitrox.sln in "Documents \ Nitrox", click Open

-Click on Generate then on Generate the solution

-Once the generation is complete, it is supposed to be written "Generation: 8 passed, 0 failed, 0 updated, 0 was ignored"

-DnSpy launcher

-Click on File-> Open and go to the folder where is to install Subnautica, go to Subnautica_Data \ Managed \ and click Assembly-CSharp.dll then Open

-Click on the search icon (the magnifying glass icon on the top right of dnSpy) and search for "GameInput"

-Double-click on GameInput (normally the first result that appears)

-Press Ctrl + F and write "awake"

-Click after the "{" and press Ctrl + Shift (or Shift) + e, a window should open

-Do Ctrl + O, normally you are still in the "Managed" folder, look for NitroxPatcher.dll and open

-In dnSpy go to the line after "GameInput.SetupDefaultBindings ((GameInput.Device) i);" and write (without the "") NitroxPatcher.Main.Execute (); " without forgetting the; (Its very important)

-Click Compile bottom right

-Then click File-> Save All-> Ok

-You can close everything

-Start Subnautica

-A "Multiplayer" button is supposed to have appeared on the main menu

-You are ready to play online

* Method if Subnautica is not in C: \ Program Files (x86) \ Steam \ steamapps \ common \ Subnautica:

-Once the file Nitrox.sln "built" (See I), an error is supposed to appear and a file named "DevVars.targets" will be created in the folder "Nitrox"

-Open the file "DevVars.targets" with Notepad and at the line <SubnauticaDir>, put the installation path where Subnautica is located, then save the file

-Then redo the manipulation of Visual Studio

To create a Subnautica server, it's very simple.

-Open the port 11000 of your box in TCP and UDP, many tutorials on how to do and depending on the type of box are available on the internet, that's why I will not detail the procedure to follow in this guide.

-Go to a site to know your IP like: http://www.mon-ip.com/

-Lancer in Documents \ Nitrox \ NitroxServer \ bin \ Debug software NitroxServer.exe

-A console opens, leave it open while you play

-Your server is online

-In Subnautica, click on Multiplayer

-Click on add server and enter a name and as IP "localhost"

-Then click on your server, enter a username and click Join

-In Subnautica, click on Multiplayer

-Click on add server and enter a name and the ip of the person who Host the server

-Then click on the server, enter a nickname and click Join

The command: mplayer playername [ip]
This command allows to connect to the server if the button "Multiplayer" does not work
Just replace "playername" with your username and [ip] with the host ip (or localhost if you are the host)

V0.1 - Creation of the Guide and Publication (02/24/2018)
V0.2- Adding a command to join a server (03/09/2018)
V0.3- Added section VII which will contain the tutorial in video (12/15/2018)
V0.4- As well as section VIII which will contain the questions that come up often (12/15/2018)
V0.5- Creation of the English Version of the guide (12/15/2018)