This information is for Vicon Evoke 1.4. For up-to-date help, see the latest Evoke documentation.

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To enable tracking of your props, you create basic objects in Evoke.

It is easiest to use the Vicon Nova kit to mount active markers on a variety of props and use them within Evoke.

You manage objects in the Tracking pane, which lists all objects tracked by Evoke. You can visually distinguish basic objects from Smart Objects by their icons.

Basic object

Smart Object

Composite Smart Object

Basic objects have a fixed pattern, so if a marker is moved you must re-create the object.

Note that you can import VSK files for basic rigid objects.

For more information, see:

See also the Vicon video:

Display the required items in the Tracking panel

By default, all items are displayed in the Tracking panel. To display only the items needed for the current task, you can display or hide items in the Tracking panel, depending on their type.

To toggle the display of tracking items:

At the top right of the Tracking panel, click the relevant button(s):

The buttons toggle the display of:

  • Basic objects (non-assigned)
  • Characters (including assigned objects)
  • Smart Objects (non-assigned)

Create basic objects

To represent your props, you create basic objects in Evoke.

To create a basic object:

  1. Place the prop with active markers attached in the volume, making sure that the markers are turned on.

    If you don't see anything in the 3D Scene, in the View Filters, ensure Unlabeled Markers is selected.

  2. In Evoke, select at least four (five or more is recommended) unlabeled reconstructions.
    The orientation of the object depends on the order in which you select the reconstructions. The first is the root, the second is the axis it will point along, and the third is the Up vector for the object. If necessary, you can change this later (see Change a basic object's origin).
  3. In the Tracking pane, click the Create button for a Basic Object.

    A new basic object is created with labeled markers and sticks


    In the Tracking pane, a new basic object (by default, called Basic Object #) is displayed.

    If your new object has a warning symbol (yellow triangle) next to it, to view information about the issue, hover the mouse pointer over the symbol. For more information, see Understand object evaluation.
  4. To rename the basic object, in the tree at the top of the Tracking pane, either:
    • Double-click the basic object to edit the name; or
    • Right-click it and then select Rename; or
    • Select the basic object and press F2; or
    • Select the basic object and in the Properties pane below, click the Name field.
  5. Enter a unique new name for the basic object.

Add a mesh to a basic object

Adding a mesh to basic objects enables you to better visualize them in the Workspace to check that they are correctly aligned and that they give the user experience that you want.

  1. In the Tracking pane, select the basic object to which you want to add a mesh.
  2. In the Properties pane, from the Mesh list, select the required mesh.
    The mesh is an FBX file with the mesh skinned to a Root bone. You can use the installed meshes, or your own FBX files, saved to C:\Users\Public\Documents\Vicon\PropMeshes.

    Your mesh is displayed in the 3D workspace.

Change a basic object's origin

The object manipulator enables you to specify a basic object's origin (ie, the center of the physical object in relation to the marker pattern that is tracked by Evoke).

  1. To activate the object manipulator:
    1. Press the space bar or click the Pause button at the bottom right of the Workspace to pause Evoke.
    2. Select the basic object.
    3. In the 3D Scene view, click the object manipulator button.

  2. In the Workspace either:
    • Drag the manipulator to move or rotate the object to the required location; or
    • Enter values in the Translation and/or Rotation fields;

      When you resume streaming, the object's orientation is updated.

      To scale the Manipulator, on the numeric keypad, press + (scale up) or - (scale down).

Note that the manipulator operates in local or global space (corresponding to the object coordinate system or the world coordinate system respectively). To switch between the two, click the icon to the left of the Object Manipulator text.

Export a basic object as a VSK

To export a basic object as a Vicon Skeleton (VSK) file:

  1. On the Tracking pane, right-click on the basic object and then select Export.
  2. In the Export dialog box, browse to or enter the location for the object.
  3. Save the VSK.

Create a custom calibration object

You can use a Vicon Active Wand to set up your volume coordinate system quickly and easily (see Set the volume origin). However, using a larger calibration object (for example, markers embedded in the volume floor and wall) can improve calibration stability and consistency over time.

You can create and export a custom calibration object from any basic object as described in Create basic objects and Export an object as a VSK.

When you export the VSK, save it to your calibration objects folder. The default location for this is:


You can now use it to set the origin of your volume:

  1. On the Camera Calibration tab, make sure the Advanced options are displayed (click Show Advanced at the top right if necessary).
  2. Ensure the Set Volume Origin section is expanded.
  3. From the L-Frame list, select the object that you created.
  4. Ensure Perform Rescale is selected. 
    This ensures that the marker distances in the L-Frame object are used for volume scaling.
  5. Click Start Set Origin.
    The button displays Set Origin and is unavailable until Evoke has enough data to set the origin, when the button is enabled.
    If issues are detected, Evoke displays a message in the Set Origin button's tooltip to help you solve the problem. For more information, see About collecting frames.
  6. Click Set Origin.
    The system scale is adjusted to provide improved calibration stability and consistency.