Hi, I got a question about how to sync a rigidbody using Unet. My setup: Player-characters (syncing fine) and a ball, all with rigidbodies. The players should be able to push the ball around. When using a networktransform with syncrigidbody on the ball and a remote clients tries to push the ball, it doesn't work because the position gets set by the server. I found the NetworkRigidbody script using the old Unity networking system and I tried editing it to get it to work with Unet, but to no avail. What is the general way to sync rigidbodies using unet/which general things would one need to change in the NetworkRigidbody script? Spoiler: Script Code (CSharp): using UnityEngine; using System.Collections; public class NetworkRigidbody : MonoBehaviour { public double m_InterpolationBackTime = 0.1; public double m_ExtrapolationLimit = 0.5; internal struct State { internal double timestamp; internal Vector3 pos; internal Vector3 velocity; internal Quaternion rot; internal Vector3 angularVelocity; } // We store twenty states with "playback" information State[] m_BufferedState = new State[20]; // Keep track of what slots are used int m_TimestampCount; void Start () { foreach (NetworkView n in GetComponents<NetworkView> ()) { n.observed = this; } } void OnSerializeNetworkView (BitStream stream, NetworkMessageInfo info) { // Send data to server if (stream.isWriting) { Vector3 pos = rigidbody.position; Quaternion rot = rigidbody.rotation; Vector3 velocity = rigidbody.velocity; Vector3 angularVelocity = rigidbody.angularVelocity; stream.Serialize (ref pos); stream.Serialize (ref velocity); stream.Serialize (ref rot); stream.Serialize (ref angularVelocity); // Read data from remote client } else { Vector3 pos = Vector3.zero; Vector3 velocity = Vector3.zero; Quaternion rot = Quaternion.identity; Vector3 angularVelocity = Vector3.zero; stream.Serialize (ref pos); stream.Serialize (ref velocity); stream.Serialize (ref rot); stream.Serialize (ref angularVelocity); // Shift the buffer sideways, deleting state 20 for (int i = m_BufferedState.Length - 1; i >= 1; i--) { m_BufferedState[i] = m_BufferedState[i - 1]; } // Record current state in slot 0 State state; state.timestamp = info.timestamp; state.pos = pos; state.velocity = velocity; state.rot = rot; state.angularVelocity = angularVelocity; m_BufferedState[0] = state; // Update used slot count, however never exceed the buffer size // Slots aren't actually freed so this just makes sure the buffer is // filled up and that uninitalized slots aren't used. m_TimestampCount = Mathf.Min (m_TimestampCount + 1, m_BufferedState.Length); // Check if states are in order, if it is inconsistent you could reshuffel or // drop the out-of-order state. Nothing is done here for (int i = 0; i < m_TimestampCount - 1; i++) { if (m_BufferedState[i].timestamp < m_BufferedState[i + 1].timestamp) Debug.Log ("State inconsistent"); } } } // We have a window of interpolationBackTime where we basically play // By having interpolationBackTime the average ping, you will usually use interpolation. // And only if no more data arrives we will use extra polation void Update () { // This is the target playback time of the rigid body double interpolationTime = Network.time - m_InterpolationBackTime; // Use interpolation if the target playback time is present in the buffer if (m_BufferedState[0].timestamp > interpolationTime) { // Go through buffer and find correct state to play back for (int i = 0; i < m_TimestampCount; i++) { if (m_BufferedState[i].timestamp <= interpolationTime || i == m_TimestampCount - 1) { // The state one slot newer (<100ms) than the best playback state State rhs = m_BufferedState[Mathf.Max (i - 1, 0)]; // The best playback state (closest to 100 ms old (default time)) State lhs = m_BufferedState[i]; // Use the time between the two slots to determine if interpolation is necessary double length = rhs.timestamp - lhs.timestamp; float t = 0.0f; // As the time difference gets closer to 100 ms t gets closer to 1 in // which case rhs is only used // Example: // Time is 10.000, so sampleTime is 9.900 // lhs.time is 9.910 rhs.time is 9.980 length is 0.070 // t is 9.900 - 9.910 / 0.070 = 0.14. So it uses 14% of rhs, 86% of lhs if (length > 0.0001f) t = (float)((interpolationTime - lhs.timestamp) / length); // if t=0 => lhs is used directly transform.localPosition = Vector3.Lerp (lhs.pos, rhs.pos, t); transform.localRotation = Quaternion.Slerp (lhs.rot, rhs.rot, t); return; } } // Use extrapolation } else { State latest = m_BufferedState[0]; float extrapolationLength = (float)(interpolationTime - latest.timestamp); // Don't extrapolation for more than 500 ms, you would need to do that carefully if (extrapolationLength < m_ExtrapolationLimit) { float axisLength = extrapolationLength * latest.angularVelocity.magnitude * Mathf.Rad2Deg; Quaternion angularRotation = Quaternion.AngleAxis (axisLength, latest.angularVelocity); rigidbody.position = latest.pos + latest.velocity * extrapolationLength; rigidbody.rotation = angularRotation * latest.rot; rigidbody.velocity = latest.velocity; rigidbody.angularVelocity = latest.angularVelocity; } } } }
You can just add NetworkTransform component to your object with Rigidbody and it will be interpolated automatically. If client want to push the object, he should send a [Command] to server.
The same issue... I do VR multiplayer. When player on the host grabs the ball (by joystick), all the players see it. But if remote client grabs ball, only he can see it, while other players see like a ball still lies on the ground.
Does the server or the client have authority over the ball object? If the server has authority, are you sending Commands to the server to move the ball or just moving the ball locally on the client?