Prerequisites:

• ~ 200gbs of free space
• Blender 4.2 LTS
• Unreal Engine 5.3.2 source code (github)
• Visual Studio 2022 (C++ workload)
• Oblivion Remastered sample project
• FModel
  

BEWARE: Working with animations in Unreal Engine happens within Unreal, because of this we need to download and setup a working project.
This takes considerable hard drive space and 1-5 hours depending on your hardware.

Configuring Visual Studio:


In visual studio make sure you have installed the 'Game development with C++' workload
We'll need this to compile our Unreal Engine build later.



Download Unreal Engine 5.3.2 Source from github

If the link won't open, note that you will need to join the Epic Games organization on github to download.
Here's an article from Epic Games on downloading source versions.

We need the source build to setup our project, release versions on Epic's launcher will not work for our purposes.



UPDATE:

There's a new community maintained fork available here
You will still need a github account linked to Epic Games to download.
This version should work the same or better than the 5.3.2 release from Epic but I haven't tested.

Compiling Unreal Engine

• Extract downloaded zip wherever you want
• Run Setup.bat
• Wait for it to finish
• Run GenerateProjectFiles.bat
• Wait for it to finish
  

A file called 'UE5.sln' should have been created if successful
This is our Visual Studio 'solution' file, it's what we'll use to compile the engine within Visual studio.

• Double click UE5.sln to open it, if it asks you which program to open with select 'Visual Studio 2022'
• Once Visual Studio opens, find the Solution Explorer (Usually it's in the top right corner)
• Expand 'Engine' folder
• Make sure the UE5 project file is highlighted (left click once)
  

• Navigate to the Build tab and find 'Build UE5'
• Left click it to begin compiling our engine
  

WARNING: This will take 30m-5hrs depending on your hardware, make sure you don't have to use your PC for heavy tasks during the process.
You can expect general slowdowns during compilation.

If your build succeeds:

• In explorer, navigate to:
  

{PathToYourEngine}\Engine\Binaries\Win64


• Run 'UnrealEditor.exe'
  

On first load, it will take a few minutes to compile all shaders.

Once you reach the project browser, you can close Unreal Engine. We only needed to run the engine at least once.



Download the Oblivion Remastered Sample Project

• Extract wherever you want
• Right click OblivionRemastered.uproject
• Switch Unreal Engine Version
• Navigate to the engine that we compiled from source
  

Note: on Windows 11 you may need to select 'Show more options' to see this legacy context menu.

Opening Our Sample Project

• Double click OblivionRemastered.uproject
• Wait for it to generate project files, this will take a few minutes
  

The project should start, note that it may need to compile shaders again first

If successful you should see something like this:

Setting up Animation Workspace


Create the following directory in the content browser inside Unreal Engine:
Content\Art\Character\Humanoid



• Click and drag the included "SK_HumanoidFull.fbx" into the created directory within the content browser
  

it should look like this upon import.
(Ignore missing smoothing group errors if you get them)



Close Unreal Engine

In explorer, navigate to your uproject and open the humanoid directory
{PathToYourProject\Content\Art\Humanoid

Copy paste the included resource 'SKEL_HumanoidSkeleton.uasset" into your project



Open the OblivionRemastered.uproject again

Open SKEL_HumanoidSkeleton
Make sure these 'Virtual Bones' are present, they're the IK leg targets in the game. Without them your feet will be stuck in their A pose in game.

• Right click our imported Skeletal Mesh and click 'Assign Skeleton'
• Select 'SKEL_HumanoidSkeleton'
• Make sure it is the file without the underscore between Humanoid and Skeleton!
• Keep all other settings default and hit Accept
• Delete the old skeleton that imported with our FBX
  



IMPORTANT!
Rename SKEL_HumanoidSkeleton to something unique, I chose 'Mike_HumanoidSkeleton'

Congrats, you're (finally) ready to begin animating!

I highly suggest you review this document to learn about how to use the rig packaged with this mod to author animations

This guide assumes you know the basics of animating so I won't go over that, and we can skip to the step where
you have already authored an animation that is ready to be imported.

Replacing animations

Use FModel to check the file path to the animations you want to replace.
Click and drag your animation FBX into the content browser in the correct destination
Folder structure and names must be the same as the game's.

Eg: I want to replace the 3rd person One Handed sprint, so my fbx should be called "A_Humanoid_OneHand_Sprint.fbx"
I should also place the file into the correct directory. In my case it's Content\Art\Animation\Humanoid\ThirdPerson\OneHanded\Locomotion\Normal

For import settings just assign the skeleton you created, you can keep all other settings the same



Configuring Packaging Settings

To package your mod, you will need to change a few settings in the project first.

In Project Settings you want to make sure you match the following settings:

• Use Pak File = True
• Use Io Store = True
• Generate Chunk = True
• Clear "Additional Asset Directories to Cook"
• Clear "List of maps to Include in a packaged build"
• Build Configuration = Shipping
  

In Editor Preferences make sure:

• Allow ChunkID Assignments = True
  

Packaging Mod Content

There's multiple ways to package content depending on your needs and how much modularity you wish to give the end user.
Although I cover two "methods" here, you can mix and match them as you see fit.

For example, say I wanted to create a mod that replaces the sprinting, idle and attack animations.
I want to package all the sprinting animations together while keeping the idle and attack animations separate. I also want to specifically make the idle optional.

I would structure my mod like this:
Custom Skeleton - Assign Chunk ID to asset directly (Method 1)
Sprinting animations - Asset Label to group animation sequences together (Method 2)
Attack Animations - Asset label (Method 2)
Idle Animation - Assign Chunk ID to asset directly (Method 1)

That would look something like this once renamed and structured in a mods folder:
MyMod_Resources_P.pak (skeleton resource, tell the user that this is required!)
MyMod_SprintingAnimations_P.pak (combined sprinting assets)
MyMod_AttackAnimations_P.pak (attack anims)
MyMod_IdleAnimation_P.pak (standalone idle replacer)

My end user could then pick and choose what to keep/remove from the provided pak files.







Method 1: Packaging multiple files in one .pak
___________________________________________________________________________

This approach is convenient for being able to group multiple assets together, if you need multiple loose files use method 2 instead, or consider
creating multiple smaller labels.

• Create a new data asset
• For the class, select "Primary Asset Label"
• Name your asset label something you'll remember (I chose 86_Sprintmod, but naming convention is arbitrary)
  

• Open your asset label
• Add all the assets you want to package in your mod (Pack your custom skeleton as well unless you're going to assign it in a separate chunk)
• Assign your asset label a chunk ID (this must be unique within your project, different pak files/assets can't share a chunk ID)
• Set Cook Rule to "Always Cook"
• Give your label a unique Chunk ID in your project (I chose 86)
• Set "Priority" to 1
  

Method 2: Packaging individual assets in one .pak
___________________________________________________________________________

This approach is good for resources or assets that you want to package separately. The downside is that it could quickly bloat your mod folder with multiple .pak files if not used conservatively.

• Right click the asset you want to package individually
• Under Asset Actions, click 'Assign to Chunk'
• Give it a unique chunk ID within your project (I chose 90)
  

When you are ready to ship your mod:

• Navigate to Platforms > Windows
• Ensure Binary Configuration = "Shipping" or "Use Project Setting (Shipping)"
• Click 'Package Project'
• Select any place to put your files
• Wait a few minutes for the project to package. This will take a long time the first time as it packages all the code and binaries for a standalone windows game.
  



Upon success:

Open your the directory you selected. For me it was inside my uproject directory (it will be a folder called "Windows")
Navigate to {Selected directory} > Windows > OblivionRemastered > Content > Paks

Here you will find your pakchunk0 (your game's content goes here by default, so this will always exist)
You will also find the pak chunks you created using Method 1 & 2
For me, it created pakchunk86 (my sprint animation sequences) and pakchunk90 (my custom skeleton resource)

You can rename these paks to anything you want but it MUST have a _P suffix

Copy these pak files into your game's pak folder in {SteamDirectory} > OblivionRemastered > OblivionRemastered > Content > Paks
I decided to create a folder structure like this
{Paks}\~mods\AltSprint


Like this you can compress the ~mods folder content into a zip file, ready to upload. (Note that the ~mods folder is not necessary for loading pak files)

Congrats! Your mod is finally ready to be distributed!