NatNet: Remote Requests/Commands

Remote Requests/Commands

The NatNet SDK features sending remote commands/requests from a client application over to a connected server application (i.e. Motive).

The SendMessageAndWait method under NatNetClient class is the core method for sending remote commands. This function takes in a string value of the command and sends it over to the connected Motive server each time it's called, and once the server receives the remote command, corresponding actions will be performed. Please note that only a selected set of commands can be understood by the server, which are listed under the remote commands chart below.

NatNet commands are sent via the UDP connection, 1510 port by default.

For a sample use of NatNet commands, refer to the provided WinFormSample.

NatNetClient::SendMessageAndWait

ErrorCode	SendMessageAndWait( const char* szRequest,
				    void** ppServerResponse, 
					int* pResponseSize );

ErrorCode	SendMessageAndWait( const char* szRequest,
				    int tries, int timeout, 
				    void** ppServerResponse,
				    int* pResponseSize );

Description

Sends a NatNet command to the NatNet server and waits for a response.

Input Parameters:

• szRequest: NatNet command string, which is one of the commands listed on the below remote commands chart. If the command requires input parameters, corresponding parameters should be included in the command with comma delimiters. (e.g. string strCommand = "SetPlaybackTakeName," + TakeName;).

• tries: Number of attempts to send the command. Default: 10.

• timeout: Number of milliseconds to wait for a response from the server before the call times out. Default: 20.

• ppServerResponse: Server response for the remote command. The response format depends on which command is sent out.

• pResponseSize: Number of bytes in response

Returns:

ErrorCode, On success, it returns 0 or ErrorCode_OK.

Remote Commands

Motive Supported NatNet Commands/Requests

Command (string)	Description	Parameters (String)	Returns
UnitsToMillimeters	Sending this command requests current system’s measurement units, in terms of millimeters. Sample command string: <source>string command = "UnitsToMillimeters";</source>	none	float
FrameRate	Queries for the tracking framerate of the system. Returns a float value representing the system framerate. Sample command string: <source>string command = "FrameRate";</source>	none	float
CurrentMode	Requests current mode that Motive is in. Returns 0 if Motive is in Live mode. Returns 1 if Motive is in Edit mode. Sample command string: <source>string command = "CurrentMode";</source>	none	int
StartRecording	This command initiates recording in Motive Sample command string: <source>string command = "StartRecording";</source>	none	none
StopRecording	This command stops recording in Motive Sample command string: <source>string command = "StopRecording";</source>	none	none
LiveMode	This command switches Motive to Live mode Sample command string: <source>string command = "LiveMode";</source>	none	none
EditMode	This command switches Motive to Edit mode. Sample command string: <source>string command = "EditMode";</source>	none	None
TimelinePlay	Starts playback of a Take that is loaded in Motive Sample command string: <source>string command = "TimelinePlay";</source>	none	none
TimelineStop	Stops playback of the loaded Take Sample command string: <source>string command = "TimelineStop";</source>	none	none
SetPlaybackTakeName	Set playback take Sample command string: <source>string command = "SetPlaybackTakeName," + stringTakeName;</source>	Take name	None
SetRecordTakeName	Set a take name to record. Sample command string: <source>string command = "SetRecordTakeName," + stringTakeName;</source>	Take name	None
SetCurrentSession	Set current session. If the session name already exists, Motive switches to that session. If the session does not exist, Motive will create a new session. You can use absolute paths to define folder locations. Sample command string: <source>string command = "SetCurrentSession," + stringSessionName;</source><source>string command = "SetCurrentSession," + "c:/folder";</source>	Session name	None
CurrentSessionPath	Gets the unix-style path to the current session folder as a string value, including trailing delimiter. Sample command string: <source>string folder = "CurrentSessionPath";</source>	none	string
SetPlaybackStartFrame	Set start frame Sample command string: <source>string command = "SetPlaybackStartFrame," + stringFrameNumber;</source>	Frame number	None
SetPlaybackStopFrame	Sets stop frame. Sample command string: <source>string command = "SetPlaybackStopFrame," + stringFrameNumber;</source>	Frame number	None
SetPlaybackCurrentFrame	Set current frame Sample command string: <source>string command = "SetPlaybackCurrentFrame," + stringFrameNumber;</source>	Frame number	none
SetPlaybackLooping	Enable or disable looping in the playback. To disable, zero must be sent along with the command. Sample command string: <source>string enablelooping = "SetPlaybackLooping";</source><source>string disablelooping = "SetPlaybackLooping, 0";</source>	none	none
EnableAsset	Enables tracking of corresponding asset (rigid body / skeleton) from Motive Sample command string: <source>string command = "EnableAsset," + stringNodeName;</source>	Asset name	None
DisableAsset	Disables tracking of a corresponding asset (rigid body / skeleton) from Motive. Sample command string: <source>string command = "DisableAsset," + stringNodeName;</source>	Asset name	None
GetProperty	Queries the server for configured value of a property in Motive. The property name must exactly match the displayed name. This request string must have the following inputs along with the command, each of them separated by a comma. Node name Property name Sample command string: <source>string command = "GetProperty," + stringNodeName + "," + stringPropertyName;</source> For rigid body assets, Streaming ID of rigid bodies can be used in place of the stringNodeName. For example, string command for getting name of a rigid body with streaming ID of 3 would be: <source>string command = "GetProperty," + "3"+ "," + "Name";</source> eSync:2: Accessing the eSync 2 requires '#' to be included at the beginning of the eSync 2's serial number. If the '#' is not present, it will make the eSync 2 inaccessible. ie. GetProperty, eSync 2 #ES002005, Source Value	Node name (if applicable) Property name	int
SetProperty	Requests Motive to configure specified properties. The property name must exactly match the respective name of setting displayed in Motive. Please refer to the Properties pane page for the list of properties. Master Rate can be used for controlling the frame rate of the camera system. For configuring camera settings remotely, use the "model #[serial]" string format. Sample command string: <source>string command = "SetProperty," + stringNodeName + "," + stringPropertyName + "," + stringPropertyValue;</source> <source>//Sets the frame rate of the camera system to 180FPS. string command = "SetProperty,Master Rate,180"; </source> <source>// Sets the gain on camera #13003 to 2. "SetProperty," + "Prime 13 #13003", + "," + "Gain" + "," + "2";</source> For rigid body assets, Streaming ID of rigid bodies can be used in place of the stringNodeName. For example, string command for enabling rigid body with streaming ID of 3 would be: <source>string command = "SetProperty," + "3"+ "," + "Active" + "," + "True";</source> eSync:2: Accessing the eSync 2 requires '#' to be included at the beginning of the eSync 2's serial number. If the '#' is not present, it will make the eSync 2 inaccessible. ie. GetProperty, eSync 2 #ES002005, Source Value	Node name. Leave it empty if not applicable. Property name Desired value	int
GetTakeProperty	Request property of a Take. You can query property of a specific Take by entering the name, or enter empty string to query the currently loaded take. Most of the properties available in the Properties: Take can be queried through this command. Sample command string: <source>string command = "GetTakeProperty," + takeName + "," + propertyName;</source><source> //Querying for EndFrame number on the currently loaded take. string command = "GetTakeProperty,,End Frame";</source>	Take Name. Leave empty for currently loaded take. Name of the property. See Properties: Take.	Depends on the property type.
CurrentTakeLength	Request length of current take. Sample command string: <source>string command = "CurrentTakeLength";</source>	non	int

Subscription Commands

Supported for Motive 3.0 or above.

Subscription commands work with Unicast streaming protocol only. When needed, unicast clients can send subscription commands to receive only specific data types through the data stream. This allows users to minimize the size of streaming packets. For more information, read through the NatNet: Unicast Data Subscription Commands page.

Following is a general format used for the subscription command strings:

• SubscribeToData,[DataType],[All or specific asset]

• SubscribeByID,[DataType],[ID]

Sample Use

Below is a sample use of the NatNet commands from the WinFormsSample application.

Start Recording

private void RecordButton_Click(object sender, EventArgs e)
{
	string command = "StartRecording";

	int nBytes = 0;
	byte[] response = new byte[10000];
	int rc = m_NatNet.SendMessageAndWait(command, 3, 100, out response, out nBytes);
	if (rc != 0)
	{
		OutputMessage(command + " not handled by server");
	}
	else
	{
		int opResult = System.BitConverter.ToInt32(response, 0);
		if (opResult == 0)
			OutputMessage(command + " handled and succeeded.");
		else
			OutputMessage(command + " handled but failed.");
	}
}

Framerate Query

// [NatNet] [optional] Query mocap server for the current camera framerate
int nBytes = 0;
byte[] response = new byte[10000];
int rc;
rc = m_NatNet.SendMessageAndWait("FrameRate", out response, out nBytes);

if (rc == 0)
{
    try
    {
        m_ServerFramerate = BitConverter.ToSingle(response, 0);
        OutputMessage(String.Format("   Camera Framerate: {0}", m_ServerFramerate));
    }
    catch (System.Exception ex)
    {
        OutputMessage(ex.Message);
    }
}

Setting name of the recorded Take

private void SetRecordingTakeButton_Click(object sender, EventArgs e)
{
    int nBytes = 0;
    byte[] response = new byte[10000];
    String strCommand = "SetRecordTakeName," + RecordingTakeNameText.Text;
    int rc = m_NatNet.SendMessageAndWait(strCommand, out response, out nBytes);
}

Setting Motive Properties

private void SetPropertyButton_Click(object sender, EventArgs e)
{
    int nBytes = 0;
    byte[] response = new byte[10000];
    string command = "SetProperty," + NodeNameText.Text + "," + PropertyNameText.Text + "," + PropertyValueText.Text;
    int rc = m_NatNet.SendMessageAndWait(command, out response, out nBytes);
    if (rc != 0)
    {
         OutputMessage(command + " not handled by server");
     }
    else
    {
        int opResult = System.BitConverter.ToInt32(response, 0);
        if (opResult == 0)
            OutputMessage(command + " handled and succeeded.");
        else
            OutputMessage(command + " handled but failed.");
    }
}