In Visual3D, you can see the Data Tree by going to the Signals and Events tab.

Signals in Visual3D are referenced by how they are presented in the Data Tree:

• Signal Type (Top level)
• Signal Folder
• Signal Name

There are only specific signal types that are allowed:

• Event_Label
• Target
• Analog
• Force
• COFP
• Freemoment
• Landmark
• Link_Model_Based
• Kinetic_Kinematic
• Derived
• Metric
• Frame_Numbers
• Header Information
• Parameters

In Expressions, signals are referenced using the following syntax:

• SignalType::SignalFolder::SignalName
• SignalType::SignalFolder::SignalName::Component

More information about the data tree can be found here.