We’ve just published the Unreal Engine movement code for Project Borealis (we’re trying to make Half-Life 2: Episode 3 based on the Epistle 3 blog post)!
You can read all about it in our developer blog: https://www.projectborealis.com/blog/developer-blog-open-source-movement/
And you can view the code (released under an MIT license) at GitHub - ProjectBorealis/PBCharacterMovement: HL2-style, classic FPS movement for Unreal Engine 4 implemented in C++
If you use this code in your own games, or have any questions — please let us know! You can email us at [EMAIL=“firstname.lastname@example.org”]email@example.com, or chat with us on Discord. You can also go to our GitHub issues, create a new issue and label it as a question.