Networked physics

The server remains authoritative. Select replication per Actor interaction pattern:

Mode	Use	Tradeoff
Default	simple replicated simulated props with limited local interaction	legacy correction overwrites local alterations; interactions degrade
Predictive Interpolation	server-authoritative props that clients predictably push/interact with	better local interaction, cheaper/less network intensive than Resimulation
Resimulation	physics Pawns/Actors needing full local prediction and authoritative replay	input/state history, rewinds/replays, higher CPU/memory/network complexity

Default mode applies velocity/correction toward the forward-predicted server state. Predictive Interpolation includes local velocity and correction timing so predicted interactions can survive. Resimulation runs the client ahead and rewinds/replays when authoritative state diverges.

For Resimulation, implement the low-level Network Physics Component in C++:

1. Define serializable input and state structures.
2. Capture player input at physics-step cadence.
3. Apply identical deterministic-enough forces/actions during prediction and replay.
4. Cache bounded history for latency/jitter budget.
5. Compare authoritative state and trigger resimulation/correction through the framework.
6. Separate cosmetic events from replayable authoritative effects to avoid duplicates.

UE 5.8 supports Predictive Interpolation and Resimulation simultaneously on different Actors and adds networked Actions. Inspect np2.PredictiveInterpolation, np2.Resim, and p.Resim console families for current tuning options rather than copying stale CVar recipes.

Test packet loss, jitter, latency, low send rate, high velocity, collisions between modes, ownership transfer, sleep/wake, spawn/despawn, and correction visibility.