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Author Topic: Back 4 Blood  (Read 2407 times)
spiritovod
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Back 4 Blood
« on: December 20, 2020, 21:37 »

Game: Back 4 Blood (steam page)
UE4 version: 4.25 (alpha) / 4.26 (full game)

All works fine - including meshes, textures and animations - with the latest umodel build (1473 at the moment). Some materials are custom. For static meshes in alpha version use 4.26, otherwise you'll get an error. For skeletal meshes in OBT version you can use latest official build with 4.25-plus override option.

For latest game versions use specific umodel build (link) - no special override is required, simply choose proper engine version. Animations from latest versions are using ACL compression, which is currently not supported by umodel.


Update: PS4 version of the game is not encrypted, but it's using customized "frozen index" format for packages. You can convert them to vanilla variant of that format with respective quickbms script from custom scripts bundle, available here. For more info please read included readme.

Update 2: Script for extracting assets from full versions of the game is now available in specific scripts bundle, available here. For more info read bottom part of this post.


* Clipboard01.jpg (140.9 KB, 2542x1229 - viewed 536 times.)

* Clipboard03.jpg (108.94 KB, 2537x1238 - viewed 59 times.)
« Last Edit: January 28, 2022, 03:55 by spiritovod » Logged
george_sears
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Re: Back 4 Blood
« Reply #1 on: August 05, 2021, 22:48 »

Current beta doesn't work with UE Viewer 1562, ue ver 25-27 tested, console says PAK has an unknown format
https://mega.nz/file/vVdxQSAR#ZCid6IQ5h6fWKrMFRX1E-Rac3hb52fiXXTFtG-eWMc8 sample
« Last Edit: August 05, 2021, 22:52 by george_sears » Logged
Digika
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Re: Back 4 Blood
« Reply #2 on: August 06, 2021, 11:36 »

No existing tools are compatible with their PAKs, including native UEpak, because they've customized it and the format is slightly different now. Normally it wouldnt be hard to RE these changes since they are probably not significant, but because they are encrypted it is kinda ogre.

I also dont believe it is actually 4.25. If they went so far to modify linked and cooker stuff they easily could hardcode 4.25 as a red herrig. Could be 4.26, could be 4.24, could be any git build with changes from any branch since they have skilled coders that can do it.
« Last Edit: August 06, 2021, 14:49 by Digika » Logged
bigrips
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Re: Back 4 Blood
« Reply #3 on: August 06, 2021, 17:16 »

All works fine - including meshes, textures and animations - with the latest umodel build (1473 at the moment). Some materials are custom. For static meshes use 4.26, otherwise you'll get an error.

Hey, sorry for registering just to bug you but do you happen to have saved any assets you dumped from the alpha? I'm only looking for Holly's playermodel (with associated textures, don't need skeleton or anything else) and it seems like dumping from this game going forward will either be difficult or outright impossible.
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spiritovod
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Re: Back 4 Blood
« Reply #4 on: August 06, 2021, 20:22 »

@bigrips: I think you can still find some working links for alpha in this topic.

@Digika: The change in package format is so insignificant that it can be fixed under a minute. Engine version doesn't really matter, but I suppose it's sort of 4.25-plus branch thing. Either way, due to custom encryption nothing of the above really matters.
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bigrips
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Re: Back 4 Blood
« Reply #5 on: August 07, 2021, 15:07 »

@bigrips: I think you can still find some working links for alpha in this topic.

Thanks for the help! I was able to get a copy of the alpha from there and extract the files I wanted.
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Krazze
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Re: Back 4 Blood
« Reply #6 on: October 08, 2021, 20:41 »

Downloaded the final version, as it was obvious it is encrypted...

And I think the spiritovod script doesn't work or it's asking for a key?
« Last Edit: October 08, 2021, 20:54 by Krazze » Logged
Fuego
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Re: Back 4 Blood
« Reply #7 on: October 24, 2021, 18:25 »

How's the final game encryption looking? I'm getting this error using 4.25, hopefully we can get a fix soon to make some dope Halloween art

Also here are some possible AES keys in case someone gets through that format issue:
1st one found: 0x0000484200409C450000C84200007A4400409C45000016430000C03F0000A040

Others: 0x00002000008000000000BE43FFFFFFFF0100000000000100E803000000008041
                                                                            
0x080000000B00000000002041640000000100000000401C4601C3CCCC00803FC7
                                                                            
0x00010000FF00000000000400000400000000803F080000000B00000000002041
                                                          
0x00002000008000000000BE43FFFFFFFF0100000000000100E803000000008041
                                                                        
0x0000FA440000FA4300409C450000FA4300007A4300409C450000FA440000FA44
                                                                            
0xCDCC4C3ECDCC4C3E0000FA430000A040000096439A99993E0000C84200001041
                                                                            
0x000048440000803F0000C84200000C420000803F00803B450000484300004842
                                                                            
0xFE0564478D0D2046890DC1458D0DBA46890DBB458D0DA445890DE546891DAE45
                                                                            
0x0000003F0000003F040000000001000040000000400000001000000002000000
                                                                            
0x9A99993E0000803F0000003F0000003F04000000060000000000003F00030303
                                                                            
0x6F168073B9B21449D742241700068ADABC306FA9AA3831164DEE8DE34E0EFBB0

0xCFC5E8CF9A2527DB4F48C41372EE1ACE6878C43382D83EF2DC7329777C34B130



* Screenshot_1.png (117.93 KB, 1073x528 - viewed 76 times.)
« Last Edit: October 24, 2021, 18:39 by Fuego » Logged
spiritovod
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Re: Back 4 Blood
« Reply #8 on: October 27, 2021, 00:33 »

@Krazze: If you'll read the post at zehnax, you'll notice that the script was developed for game packages with already decrypted indices (table of contents). That's how it worked in OBT times, but since I don't own full game, there is nothing I can do with more recent releases.

@Fuego: Only the last line contains actual key (the rest is just random garbage), but it's useless anyway, since the game is using custom encryption. You could at least read the first post.
« Last Edit: October 27, 2021, 00:37 by spiritovod » Logged
spiritovod
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Re: Back 4 Blood
« Reply #9 on: January 10, 2022, 01:36 »

First post is updated with more info about latest game versions, based on PS4 version, which is not encrypted, but using customized "frozen index" format (those changes are adopted between all builds, regardless of particular format). It's now using customized 4.25-plus engine, but from the umodel side it's more like 4.26. Also, full version is using ACL compression for animations and it seems they're somehow customized as well, because they don't work with akderebur's ACLViewer.

Update: akderebur confirmed that rotation data is modified or obfuscated, and it can't be easily fixed, because meaning of those changes is unknown. For now only animations from alpha version are playable.
« Last Edit: January 18, 2022, 04:58 by spiritovod » Logged
spiritovod
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Re: Back 4 Blood
« Reply #10 on: January 22, 2022, 17:02 »

Full PC versions of the game are now also extractable with specific script. First post is updated with respective info.
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09williamsad
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Re: Back 4 Blood
« Reply #11 on: January 23, 2022, 18:33 »

Full PC versions of the game are now also extractable with specific script. First post is updated with respective info.

I have been trying to convert the steam version, and keep getting "Serializing behind stopper" and "Unable to read" bytes errors.
I have tried 4.25 and 4.26, latest and Back4Blood versions of umodel, disabling some data types, etc.

Either I have missed something or the Steam version is different to the EGS version.

Which umodel client, bit type and unreal version did you use?

Steam version samples: https://mega.nz/folder/qewgCApK#KUePBIkgV8uZWQLevmoAhg
Umodel versions: 1585 and B4B 1579
BMS script: unreal_tournament_4_0.4.25c_back4blood.bms, script was not edited.
Game version: full
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spiritovod
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Re: Back 4 Blood
« Reply #12 on: January 23, 2022, 21:35 »

@09williamsad: You didn't extract them properly, you should run quickbms with -o -C parameters or allow overwriting manually when asked (apparently you've picked automatic renaming option instead). Then specific build should work with 4.26 override on any latest version, except for animations.
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