DataHandler function is not called

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DataHandler function is not called

Post by Jacobo » Tue Sep 16, 2014 12:15 am


I am trying to install and stream data from Arena (1.8) using the NatNet SDK (2.2). After installing and calibrate the system I run the Sample Client to check that everything is working.

The first part that I recieve is the header, which I think is ok. The only line that be a problem is:

[Client] Server returned NAT_UNRECOGNIZED_REQUEST

After that when I start to send data (actually the streaming has to be on before I start the data) I recieve :

[Client] Received command from Command=7, nDataBytes=220

Until the prgram fails. But I don`t see any of the info that the funcion DataHandler shoul be printing which I suppouse that is DataHandler the function that is not being called.

For the moment I am executing the program in the same computer than Arena, and I turned off all the firewalls/antivirus.

Thanks for your help.

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Re: DataHandler function is not called

Post by NaturalPoint-Dustin » Thu Sep 18, 2014 5:06 pm

Do you have access to later versions of Arena or Motive? I read through the changelog and noticed some improvements to NatNet with Arena after the Arena 1.8 Beta release. I can review your license information if you create a ticket at
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Re: DataHandler function is not called

Post by morgan » Thu Oct 02, 2014 10:17 am

[Client] Server returned NAT_UNRECOGNIZED_REQUEST

Is OK and can be expected when the server doesn't recognize the request.

We're you able to get streaming working from the data handler callback?

If not I would first test using one of the pre-compiled samples that ship with the NatNet SDK (WinForms is a good one). This will indicated whether its a code issue, or a networking issue.

If the pre-compiled samples are not receiving data, some things I would try:

- Antivirus and firewall are disabled. Note this is not a requirement, but useful for testing.
- Motive/Arena streaming is enabled and tracking or playing back data.
- Motive/Arena streaming IP addresses are configured correctly
- don't change the multicast address
- use local loopback ( for both server and client when streaming on same machine
- Try Unicast (change on both client and server) to isolate whether multicast packets are being filtered by your network topology

hope this helps,


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