AUMSS/Runtime/PickupSpeedLimiter.cs

using UdonSharp;
using UnityEngine;
using VRC.SDK3.Components;
using VRC.SDKBase;

[UdonBehaviourSyncMode(BehaviourSyncMode.NoVariableSync)]
[DisallowMultipleComponent]
[AddComponentMenu("Artyom Scripting System/Pickup Speed Limiter")]
public class PickupSpeedLimiter : UdonSharpBehaviour
{
    public float maxSpeed = 5.0f; // Maximum allowed speed for the pickup
    public bool debugSpeed;
    private VRC_Pickup pickup; // Reference to the VRC_Pickup component
    private Rigidbody rb;
    private bool synced; // Has VRCObjectSync: only its owner limits it

    void Start()
    {
        pickup = GetComponent<VRC_Pickup>();
        rb = GetComponent<Rigidbody>();
        synced = GetComponent<VRCObjectSync>() != null;

        if (pickup == null || rb == null)
        {
            Debug.LogError("[AUMSS] Pickup Speed Limiter: needs a VRC_Pickup and a Rigidbody on this GameObject.");
            enabled = false;
        }
    }

    // FixedUpdate: once per physics step, so no step runs over the limit
    void FixedUpdate()
    {
        if (pickup == null || rb == null) return; // Not set up (enabled = false only takes effect next frame)
        if (pickup.IsHeld) return;
        if (synced && !Networking.IsOwner(gameObject)) return; // Anyone else would fight the sync

        Vector3 velocity = rb.velocity;
        if (velocity.sqrMagnitude > maxSpeed * maxSpeed)
        {
            if (debugSpeed) Debug.LogWarning("[AUMSS] Pickup Speed Limiter: " + gameObject.name + " at " + velocity.magnitude.ToString() + ", limited to " + maxSpeed.ToString());
            rb.velocity = velocity.normalized * maxSpeed;
        }
    }
}