How to play with 8 survivors in custom L4D1 maps

Release: 28 July 2017

Want to play Rayman1103's United We Stand Co-op mutation mod in custom L4D1 map campaigns? You are able to play with 8 survivors in all L4D2 maps, but having trouble doing the same in custom L4D1 maps? No problem! Fixing it is just piece of cake if you have tools standby!


Hello again, and welcome back to my Left 4 Dead 2 guideline world. Few days ago, I made my very first guideline which is regarding Zoey's problem in Rayman1103's United We Stand Coop mutation mod. Her problem is because she's a fake Zoey bot (since implanting real Zoey bot will result in game crash at Windows), her incapped image, viewmodel arms, and icon are all missing, with her name changed to "Survivor" if she was brought from dead. I've said this that the simplest solution is to get Sourcemod and install Zoey's Send Proxy plugin, thereby using her m_survivorcharacter 5 skin personality. By doing this, you'll restore all her icon, incapped image, arms, and Zoey real name not the "Survivor" bug.

To be honest with you gamers, I wouldn't come here and bother write these out if there are already guidelines posted here or elsewhere earlier. But that's not the case as no one really tried post it, hence this is why I feel like I should volunteer myself to share solutions to fix unresolved mutation mod problems that many people had been complaining for months. Now I'm not here to brag how holier my solution is nor I'm monopolizing my solution. I admit my solutions discovered would not be 100% satisfactory to all gamers (for example my first Zoey's solution post still left out her gender problem), but at least I'm trying to convey a message to the community: that such problems hanged in limbo for months or years seemed impossible to fix can always be solved one day, and for that I would really urge L4D2 communities to cooperate, find, and share better solutions to fix these game bugs. It almost seems impossible until its done.


Introduction

Anyway, today I would like to share my second L4D2 guideline. Again, this is also about Rayman1103's famous mutation mod called United We Stand Coop which we will play 8 survivors (L4D1 + L4D2 survivors) together. The thing is, while we are able to play this 8 survivors mutation mod ONLY in all L4D2 map campaign, sadly we cannot play the same thing at custom L4D1 map campaign.

To explain this in laymen way, this is because L4D2 game script contains support for L4D1 bots. It all started out when Valve announces downloaded contents (DLC) like The Passing and The Sacrifice, thereby officially porting L4D1 non-playable characters to L4D2 game engine. But there's none of these in vice-versa. There is no support for L4D2 bots in L4D1 DLC scripts.

Just imagine, you rewind back the clock and assumed L4D2 didn't exist in January 2009. People like Coach, Nick, Ellis, and Rochelle doesn't exist. There's only Bill, Zoey, Francis, and Louis. Got the idea now? So thats how L4D1 DLC scripts are designed. The bot script works only one way, not two ways. That's why we can bring L4D1 bots to L4D2 campaigns, but we cannot bring L4D2 bots to L4D1 campaigns (with the exception of official L4D1 maps, but different than what you think). If you try play United We Stand Coop (UWSC) in custom L4D1 maps, you will only end up getting 2 Zoeys, 2 Bills, 2 Francis', and 2 Louis', and not L4D2 survivors. Below images are examples of what happens if you attempt to play UWSC mod in custom L4D1 campaigns:

Dark Wood (Extended)

Pitch Dark Mesa

See what I mean? You can't just play UWSC mod in L4D1 custom campaigns using L4D1 survivors. By doing that you only will bring another L4D1 survivors' clones. So the only trick here is to play them basing on L4D2 survivors mode.

That's how Rayman discovered the trick for the 6 official L4D1 maps. If I'm not mistaken, what he did was he just needs to first swap the map campaign base survivors with L4D2 survivors set. By doing this, only then people can play 8 survivors mode in L4D1 campaigns. However, you will only play based on L4D2 survivors set and listen to L4D2 themes, rather than basing on L4D1 survivors set or L4D1 themes. L4D2 survivors will always be the masters of the game engine while L4D1 survivors are merely backups.


8 survivors mod in No Mercy map, the first L4D1 official campaign

Things need to prepare

* L4D2 Authoring Tools/SDK Tools
* VPK.exe (make sure SDK Tools is fully updated)
* GCF Scape

Once you understand Rayman survivor swapping trick as I do, then you'll realize that same thing needs to be done for custom L4D1 map campaigns in order for 8 survivors to appear there. So how do we do this?

Firstly, you must ensure your latest updated SDK Tools aka L4D2 Authoring Tools are installed in your L4D2 game directory. I'm not going to teach this part though since I assume you already have your tools prepared. For those who haven't got it, just read here to get the SDK Tools yourselves. Secondly, make sure you got the VPK.exe on standby. In following guideline you will need it to compile map campaigns back to VPK file. If you want to test practice how to compile VPK files, read here.

Lastly, you must get GCF Scape (click here). They are important tool used to extract contents inside VPK files.

Extract contents from VPK file

Go download any random custom L4D1 map campaigns you like to play. Needless to say, they will be downloaded in the form of VPK file. VPK means Valve Pack format, they are uncompressed archives used to package game content applicable for certain Valve games only. VPK stores mostly sounds, materials, models, maps, particles vital for the game content. Both official and custom map campaigns' content are mostly stored in VPK files.

Once you already got those map campaign, what you need to do is create a new folder, then rename it after the same map campaign. Lets say I want to play Pitch Dark Mesa campaign, so I will create a new Pitch Dark Mesa folder in this regard. Next, extract ALL the contents from inside VPK file of your chosen L4D1 campaign by using GCF Scape, then place it to your new folder. Normally it will contain folders like maps, materials, models, missions, scripts, and sometimes sounds. Also included files are addoninfo.txt and addonimage.jpg. Whatever contents you got in the VPK file, just extract everything to the new folder which you will soon compile them back again.

Switching map campaign survivors

We're going to the technical part now. In your new L4D1 map folder you extracted all the contents to, go to missions folder. Then open up the only map campaign mission text file in Notepad.

In the note content, you will see all the important lines which will determine how a map campaign is set. This is where it decides what map posters to load, which sets of survivors played, how many maps, and what type of mutations available.

Now here comes the most important part. Search the line "survivor_set". It will be followed by an integer value which is either "1", that is for L4D1 survivors, or "2", which is L4D2 survivors. Since this map campaign is set to 1, you must now change it to "2", thereby allowing the map campaign to load up L4D2 survivors set.

There, not so difficult eh? Well, its almost done now. Just one more thing.

Sometimes, you will notice that the missions text file will include lines that mentions loading posters' survivors name. It will either shows up something like "francis_player_name_x" and "francis_player_name_y", followed by Zoey, Bill, and Louis.

For this case, what you need to do is:

- Change "bill_player_name_x" (and y) to "gambler_player_name_x" (and y)
- Change "louis_player_name_x" (and y) to "coach_player_name_x" (and y)
- Change "zoey_player_name_x" (and y) to "producer_player_name_x" (and y)
- Change "francis_player_name_x" (and y) to "mechanic_player_name_x" (and y)

NOTE:
Gambler means Nick
Coach means Coach
Producer means Rochelle
Mechanic means Ellis

In some custom map campaigns, the "poster" line will also shows up a sub-line called "character_order", followed by the "namvet;biker;manager;teengirl" string.

Just change it to "gambler;mechanic;producer;coach", or whichever survivors name order you like.

Recompile into VPK file

That's it! Save the mission text file. You are now finished! Drag your new L4D1 map folder into the VPK.exe.

It will automatically compile them into a new VPK file. Once its done, just do your normal way, put them into the addons folder!

What are you waiting for? Go test it out yourself! Oh, and you better pray that it works...

Go play L4D2 game and choose that custom L4D1 map campaign. At last....

See how that changed? That means you are doing it right. Now finally go play United We Stand coop mod, or just type console "map [your map codename] unitedcoop". You are all set to go!!!

See that? Works 100% fine! L4D2 survivors finally entered in L4D1 custom maps but in reverse engineering.

Now go try other L4D1 maps. Let's take Dark Wood (Extended) as another test. Do every same steps, and you will get the same thing:

Weird to see Zoey, Louis, Bill, and Francis in the poster, but it was Nick, Rochelle, Coach, and Ellis names that show up? Not really. Its just how it turns out once swapping the survivors set.

Some important notes when swapping survivors:

1) Remember that by changing survivors set, you can only play from L4D2 survivors perspective from now onwards, not L4D1 survivors perspective. As mentioned earlier, this means you will see symptoms like only listen to L4D2 music themes, not L4D1 themes. L4D2 survivors will also be present in cinematic scenes, while L4D1 members will be absent from scenes.

2) If you still wants to play with L4D1 survivors, you can either switch bots by typing "sb_takecontrol Bill" at console, or get Rayman's Admin System, or download whatever available sourcemod plugins such as Survivor Bot Select to allow taking control bots easily. 
[WARNING: Playing L4D1 survivors is strongly NOT recommended as there is very high risk of game crashing. Choose plugins wisely to stabilize the mod]

3) If you try swap survivors set in certain custom L4D1 maps that have special mods like new characters models, skins, or special cinematic scenes meant for L4D1 survivors, do expect bad case scenarios like original cinematic scenes to be skipped or no talker scripts for L4D2 survivors will be heared. However with L4D1 survivors presence, it is possible for L4D1 survivors to hear their talker scripts originally scripted in L4D1 maps.

4) If game crash over certain extraordinary L4D1 mod maps, forget swapping it.

5) Now that you have the knowledge to swap survivors which one needs to change the "survivor_set" value, you can actually do that vice versa in custom L4D2 map campaign whereby you want L4D1 survivors to play at custom L4D2 maps. Just set the value to "1" and all good to go. Beware, you will lose the privilege to play 8 survivors in any modified L4D2 maps.


That's about it from my guideline today. Again, please don't expect perfect and beautiful results by doing these. Hence the reason I added these notes. However, this is the best solution I can offer for those wanting to play 8 survivors in L4D1 campaigns so bad. Everyone is still welcome to offer their better solutions. 

As it always, I will post any new updates if I made any new discoveries. Thank you very much and have a nice day slaughtering zombies (+18 actions discretion is advised).