CF3 Interaction Authority — UE5 Multiplayer Interaction System with Late-Join Proof

Hi everyone,

This is CF3 Systems.

I’ve released CF3 Interaction Authority, a UE5 multiplayer interaction system focused on server authoritative validation, replicated state, and late-join-safe interaction examples.

The goal is to solve a common multiplayer problem:

client sends interaction intent

server validates the target

server applies the result

replicated state rebuilds correctly for other clients and late joiners

Included demo examples:

replicated door interaction

replicated pickup interaction

persistent button interaction

momentary button interaction

optional interaction prompt UI

range and line-of-sight validation

The system is designed so the authority logic stays separate from the demo UI and player setup.

Proof video:

Fab product page:

Documentation:

This thread is for product questions, setup help, feedback, and future update notes.

Feedback on the proof video, documentation, or multiplayer setup flow would be appreciated.