TransSync

Namespace: K13A.TSMP

TransSyncAttribute marks fields that TSMP should encode into variable state messages.

[TransSync("example.value")]
public int syncedValue;

The field must be discoverable by TSMPSetup. After adding or removing a [TransSync] field, run Apply Setup.

Properties

Property	Type	Default	What it does
Key	string	null	Stable identifier used to calculate the variable hash. If omitted, TSMP uses the field name. Sender and receiver fields must use the same key, network ID, and value type to match.
Direction	NetworkSyncDirection	SendReceive	Controls whether the setup process puts this field in the encoder binding table, the decoder binding table, or both. Use this to separate source fields from receive/display fields.
Priority	int	0	Stored in the generated receiver binding table as an ordering hint for tooling and future scheduling. The current runtime does not use it to throttle or reorder variable writes.
SendOnChange	bool	true	Metadata for change-based sending. It is accepted by the attribute but the current encoder still samples bound fields during encode. Do not rely on it as a runtime bandwidth limiter.
MinSendInterval	float	0	Metadata for rate-limited sending. It is accepted by the attribute but the current encoder does not enforce per-field intervals. Use component-level logic or packed byte[] flags when you need custom pacing.
EnabledBy	string	null	Name of a bool field or property on the same component. When Apply Setup builds bindings and the member is false, this field is omitted from the generated binding table.

Use a clear, stable key such as transform.packed, animator.bytes, or counter.value. Do not use a key that changes at runtime.

Key

Key is the wire identity of the field. It lets two different field names synchronize as the same variable:

public class ChatInput : TSMPNetworkBehaviour
{
    [TransSync("chat.text", Direction = NetworkSyncDirection.SendOnly)]
    public string outgoingText;
}

public class ChatOutput : TSMPNetworkBehaviour
{
    [TransSync("chat.text", Direction = NetworkSyncDirection.ReceiveOnly)]
    public string incomingText;
}

Both fields use chat.text, so TSMP gives them the same variable hash. Keep this key stable after publishing a world. If you rename or change the key, run Apply Setup again and make sure all senders and receivers are updated together.

Direction

Direction decides which side of the generated binding table can use the field.

Value	Typical use
SendReceive	Simple mirrored state where the same field can be encoded and also receive decoded values. Good for one-way sender and receiver objects that are not the same local field.
SendOnly	Source/input fields. The encoder can read the field, but the decoder will not write back into this field. Use this for local UI input, local tracking state, or self-loop tests.
ReceiveOnly	Display/output fields. The decoder can write into the field, but the encoder will not read it. Use this for text labels, proxy avatars, remote-only state, or delayed loopback display.

For a loopback test such as instance A encoder -> stream -> instance A decoder, prefer SendOnly on the input field and ReceiveOnly on a separate output field. If one SendReceive field is used for both, delayed frames can overwrite the current local value with older received data.

Priority, SendOnChange, and MinSendInterval

These options describe intended send policy, but they are not a per-field scheduler in the current runtime.

• Priority is recorded in receiver bindings and can be used by tools or future scheduler work.
• SendOnChange does not currently stop the encoder from sampling the field each encode.
• MinSendInterval does not currently throttle that field by time.

When you need real bandwidth control today, put your own logic in TSMPBeforeEncode() and write either an unchanged value, an empty packet, or a packed byte[] with flags. For high-frequency data, one packed field is usually cheaper and easier to control than many scalar fields.

EnabledBy

EnabledBy is best for setup-time optional fields:

public bool includeVelocity = true;

[TransSync("velocity", EnabledBy = nameof(includeVelocity))]
public Vector3 velocity;

When Apply Setup runs, TSMP checks includeVelocity. If it is false, the field is not added to the generated binding table. For uploaded Udon worlds, treat this as a binding-generation option, not as a high-frequency runtime toggle. If you need to change what data is sent every frame, keep the binding present and encode that choice inside a packed byte[].

NetworkSyncDirection

Value	Meaning
SendReceive	Field can be sent and received.
SendOnly	Field is encoded but not applied on receive.
ReceiveOnly	Field is applied on receive but not encoded.

Direction is resolved during setup. Re-run setup after changing it.

Supported value types

• bool
• int
• float
• Vector2
• Vector3
• Quaternion
• string
• byte[]
• bool[]
• int[]
• float[]
• Vector2[]
• Vector3[]
• Quaternion[]
• string[]

For high-frequency data, prefer packed byte[] fields.

Binding rebuilds

Key, Direction, value type, and EnabledBy affect generated bindings. After changing any of them, run Apply Setup on TSMPSetup. In uploaded VRChat worlds, TSMP uses those generated tables instead of runtime reflection.

Payload advice

Each separate field has message overhead. A few scalar fields are fine, but repeated high-frequency values should be packed.

Prefer:

[TransSync("pose.packed")]
public byte[] poseBytes;

over many individual bone, blend shape, or transform fields.