CustusX  16.5
An IGT application
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Tracking Setup


CustusX supports the NDI Polaris and Aurora tracking systems though IGSTK, It is assumed that the NDI driver are installed as described here:

NDI Installation .

Platform-specific issues


Run the following shell lines after installing the Track application:

Setup connection between CustusX and IGSTK:

    sudo mkdir -p /Library/CustusX/igstk.links
    sudo chmod a+rwx /Library/CustusX/igstk.links


The folder


is required to exist and be writable, but is created by the installer.


CustusX assumes that NDI connects through COM-port 9. If this is not the case, change manually.

Tool File setup

Each tool needs an associated tool file. Prior to use, the tools must be configured in the Preferences->Tool Configuration panel.

A fex tool files are supplied with the application (Look in the config/tool/Tools/Shared folder). Use these as a starting point to creating your own.

Important content:

  <name>My pointing device</name>
  <clinical_app>Laboratory Laparoscopy</clinical_app>


  • type: Identifies the type of tool. Must be one of {reference, pointer, usprobe}
  • id: A unique id used throughout the application.
  • geo_file: The file visual_representation.stl contains a 3D graphical representation of the tool, that will be shown in the 3D scene. The drawing is done in the Tool (t) space.
  • rom_file: The NDI ROM file for the tool.
  • cal_file: The file contains the tool calibration sMt. The file must contain 16 numbers representing the 4x4 affine matrix sMt. If no file is present, an identity matrix is assumed.


If you encounter problems:

  • Verify that the tracking device works outside of CustusX, using the supplier's native application (e.g. NDI Track)
  • Read the error messages in the CustusX Console.
  • Check the tool buttons in CustusX, lower right corner.
    • No buttons: Tools are not configured correctly. Check tool files.
    • Gray: Tools are configured correctly, but not connected to hardware.
    • Red: Tool is connected but not visible. Not necessarily a problem. Check that the tool is within the field of view of your hardware.
    • Green: Everything OK and tracking.


For a more detailed discussion, refer to (TBD: papers on custusx accuracy).

  • Quality of Tool Calibration sMt.
  • Damage to the tool. If the tool contains a pointing device, verify it is not bent since last calibration
  • Accuracy of tracking hardware. Refer to supplier. Some hints:
    • NDI Aurora: Magnetic metal in the FOV, moving to the edge of FOV.
    • NDI Polaris: The spheres should in theory be brand new for every use (NDI recommendation). In practice (outside of the OR) you can reuse spheres, but the accuracy will then drop somewhat, but still be within 1-2mm. Make sure the spheres are not damaged. For example a missing part (or a drop of liquid) on the side might shift the center position by up to half the sphere diameter.
    • NDI Polaris: Position in FOV and orientation of the spheres.