Monitors enable you to specify conditions or events during motion capture sessions, and to interact with them. For example, you can create a monitor for a graphed model output (such as the subject raising an arm to a certain height, or the subject's left knee angle exceeding 180 degrees), and then configure it on the Monitors tab of the Communications window to trigger one or more actions (such as an event on the time bar or a tone sounding) when the model output matches a condition you specify.
You create monitors in the Graph view. You can then configure the monitors in the Monitors tab of the Communications pane.
For an example of creating a monitor, see Create a joint range overlay monitor (part of a biomechanics workflow).
To create a monitor:
- Decide on the elements you wish to monitor (trajectories, model outputs, devices, or joints).
- In a Graph view, click the Differentiate the graph button and from the dropdown list, select either:
- The current variable ( x ); or
- Its first derivative, that is, its velocity or angular velocity (x'), or
- Its second derivative, that is, its acceleration or angular acceleration (x")
For example, a graph of a trajectory will have X, Y, and Z axes, but when differentiated to x' (velocity), the axes will change to X', Y', and Z' axes.
- Click the Choose the components button and select the graph components that you want to plot in the Graph view (the options depend on your choice in the previous step).
- On the Graph view toolbar, click the Create a Monitor button.
The monitor is added to the Monitors list in the Monitors communications pane.
The monitor takes the name of the component you selected. For example, if the Graph view you've selected shows X, Y, and Z for the LeftAnkleForce, three monitors are created: LAnkleForce:X, LAnkleForce:Y, and LAnkleForce:Z.Tip
If you select multiple components for your Graph view, a monitor is created for each component (e.g., x, y, z). You can select and remove one or more monitors that you don't need from the Monitors list, or click Clear to remove all of them.
You can now configure the monitor, for example to specify a monitor threshold and trigger conditions that will trigger an action.