NatNet: Remote Requests/Commands

Remote Requests/Commands

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The NatNet SDK features methods for sending remote commands and requests from a client application over to a connected server application. The SendMessageAndWait method within a NatNetClient object passes one of the NatNet commands each time it's called. NatNet commands are sent via the UDP connection; 1510 port by default. Once a NatNet server application (e.g. Motive) receives the remote command, corresponding actions will be performed.

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.

• 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: Application defined response.

• pResponseSize: Number of bytes in response

Returns:

ErrorCode, On success, it returns 0 or ErrorCode_OK indicating that the remmote message have been successfully delivered.

Motive Supported NatNet Commands/Requests

Command (string)	Description	Parameters	Returns
UnitsToMillimeters	Request current system’s units, in terms of millimeters	none	float
FrameRate	Request current system’s tracking framerate	none	float
StartRecording	Start recording	none	none
StopRecording	Stop recording	none	none
LiveMode	Switch to Live mode	none	none
EditMode	Switch to Edit mode	none	None
CurrentMode	Request current mode	none	int
TimelinePlay	Start take playback	none	none
TimelineStop	Stop take playback	none	none
SetPlaybackTakeName	Set playback take	Take name	None
SetRecordTakeName	Set record take name	Take name	None
SetCurrentSession	Set current session	Session name	None
SetPlaybackStartFrame	Set start frame	Frame number	None
SetPlaybackStopFrame	Set stop frame	Frame number	None
SetPlaybackCurrentFrame	Set current frame	Frame number	None
CurrentTakeLength	Request length of current take	None	Number of frames (int)
AnalogSamplesPerMocapFrame	Request number of analog samples per motion capture frame	None	int

Sample Use

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

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.");
	}
}