SmoothSync

Client-side fix for movement jitter in multiplayer Valheim. Optional: only the players who install it benefit, the server does not need it and nothing is enforced.

Why vanilla jitters

• Objects owned by another player (ships, carts, players, creatures) are positioned in FixedUpdate (50 times a second) by writing the transform directly. That bypasses Rigidbody interpolation, so on a 144-240 Hz screen they move in steps.
• Standing still on a ship you do not own teleports your own character onto the ship every physics step, which makes your character and the camera step as well. Only the ship's owner gets the smooth (velocity) path.
• Owners send their state 20 times a second.

What it does

• Remote ships, carts, players and creatures are driven with velocity (owner's velocity + a short time-based correction) and rendered with Rigidbody interpolation: smooth at any frame rate, robust to packet timing.
• Standing on someone else's ship uses the same velocity correction the owner uses instead of the teleport.
• Your client sends the objects it owns twice as often (40/s).
• Taking the helm makes you the ship's owner (no input delay for the driver).
• Logs frames slower than 50 ms with garbage-collection and object-creation counts (diagnostics, can be turned off).

All parts can be toggled in the config (nuckflare.smoothsync.cfg).