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

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.

The following topics provide more information on how to work with basic objects.

See also the Vicon video:

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. If you're using Nova or SuperNova strands, make sure that the markers are turned on.

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

2. In Evoke, select at least four unlabeled reconstructions – five or more is recommended (Alt+drag or drag only, if the option Alt key to select in views is cleared in Preferences).
   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 Setup panel, click the Create button for a basic object.

   

   A new basic object is created with labeled markers and sticks.

   

   In the Tracking panel, a new basic object (default name: BasicObject#) is displayed.

   

   Tip
   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 either:
   
   • In the tree at the top of the Tracking panel, do one of the following:
     • Double-click the basic object; or
     • Right-click the basic object and then select Rename; or
     • Select the basic object and press F2.

   Or

   • In the Tracking Setup panel, click in the Basic Object 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 panel, 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 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.

     Tip
     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 buttons to the right of the Object Manipulator heading .

In the 3D View, you can align a selected object's axes to the global axes, a selected marker, or to the center of multiple selected markers. To do this, select the relevant object(s) or marker(s), activate the Object Manipulator and then expand Alignment Tool at the bottom. For more information, see Understand the alignment tool.

Add or remove markers – basic objects

Evoke enables you to add markers to a basic object or remove markers from a basic object. This is particularly useful, if, for example, a marker fails or falls off the object.

If a marker is removed from a basic object, you can manually select and remove the marker from the reconstruction. Similarly, if a marker is added, you can assign it a label and make it part of an existing reconstruction.

To remove a marker from a basic object:

1. In the Tracking panel, ensure that the required basic object (which must have more than four markers) is selected, and in the 3D View, select the labeled marker that you want to remove.

2. In the Tracking Setup panel, go to the Modify Object line and click Remove Marker.

   

   The marker becomes unlabeled and is removed from the object.

To add an unlabeled marker to a basic object:

1. In the 3D View, select the required unlabeled marker.
2. At the top of the Tracking panel, Ctrl+click to select the required basic object.
3. In the Tracking Setup panel, in the Modify Object line, click Add Marker.
   The unlabeled marker is now labeled and added to the selected object.

Export a basic object as a VSK

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

1. On the Tracking panel, 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 quickly set up your volume coordinate system (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.

For information on how to do this, see Scale calibration and set a fixed origin.