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Mocap System

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Nicholas Sutton edited this page Jun 9, 2026 · 3 revisions

Our lab uses an OptiTrack Motion Capture system. For general information, please view the following resources:

Streaming Overview

To use data from the mocap system, we developed a system daemon and libraries called Wyrm to stream data from a machine running the Motive software to client computers.

Terminology

  • Motive: The software developed by OptiTrack to run the motion capture system and act as a server that streams motion capture data over a network.
  • NatNet: The SDK developed by OptiTrack to create Client applications that connect to the Motive server.
  • Wyrm: A System daemon and set of libraries used to interact with the NatNet SDK and simplify writing client applications for Motive.
  • Zenoh: A data communication protocol that Wyrm uses to send Motives data to client applications.
  • Server: The machine running the Motive Software.
  • Client: Any machine that is connecting to the Motive software over the network.
  • Network Interface/Interface: The method of connecting the server to the client. This could be a WiFi card, a network adapter, or an Ethernet cable.

Motion Capture Computer Installation and Configuration

These instructions assume that you have followed OptiTrack's instructions for installing Motive.

Motive Streaming

  1. Go to the settings->Streaming in Motive
  2. Under the NatNet settings, select Enable
  3. Ensure that Transmission Type is set to Unicast
  4. Set the Local Interface IP Address to the IPv4 Address of the network interface connected to the client. You can check the network interface by running the following command in the terminal.
ipconfig

Note

Windows often resets the firewall and network settings. If you encounter issues when streaming, ensure that these settings are correct.

Windows Network Connection Profile

  1. Press Windows Key + X
  2. select Terminal(Admin)
  3. In the terminal, type the following command:
Get-NetConnectionProfile
  1. Locate the network interface connected to the client.
  2. If the Network Category of the interface is Public run:
Set-NetConnectionProfile -InterfaceAlias 'your_interface_alias' -NetworkCategory Private
  1. Check that the Interfaces Network Category is now private:
Get-NetConnectionProfile

Windows Firewall settings

  1. Search for and select the Windows Defender Firewall application in the Windows search bar.
  2. Select Advanced Settings
  3. Select Inbound Rules
  4. Locate any rule with the name Motive
  5. All of these rules should have their Profile set to Private and Enabled set to Yes
  6. To Enable connections: Right-click->Properties->General->Allow the connection
  7. To set the Profile: Right-click->Properties->Advanced->Private
  8. Select Apply->Ok

Client Configuration

  1. Connect to the Windows Computer using Ethernet or another Network Interface.
  2. Locate the Ethernet Interface in your network settings.
  3. Ensure that the IPv4 Address of your network Interface is on the same subnet as the IPv4 address of the Windows computer. Our system is currently set to use 169.254.54.134 for the server, so a client IP would be 169.254.54.xxx # example: 169.254.54.135
  4. Ensure that the Wyrmd Daemons configuration file matches the settings in Motive.
  5. You may need to run the following command to let the Motive Server and Zenoh through your Firewall:
# Motive
sudo firewall-cmd --permanent --add-source=<motive.server.ip> --zone=trusted
sudo firewall-cmd --reload

# Zenoh
sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" destination address="224.0.0.224/32" accept'
sudo firewall-cmd --permanent --add-port=7446/udp
sudo firewall-cmd --reload

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