Specifications

calculation of any sort of forces. This means that you can run KinematicAnalysis as soon as you

have the movement defined uniquely. You don't need any muscles in the model for this one.

• InverseDynamicAnalysis. This is a simulation of the forces involved in the given movement or

posture and whatever can be derived from them. The InverseDynamicAnalysis uses the

KinematicAnalysis as a subroutine, so this requires a correctly defined movement or posture as well

as the muscles or motors necessary to drive the model.

Each of these studies, when executed, assembles the output they generate in the Output section under the

study's tree.

Running operations

You execute operations through the wide, narrow control pane that's usually located at the bottom of the

screen. This is usually referred to as the Operation Window.

The lower portion of this pane is just the message window where the system writes various messages and

dumps object properties when you double-click them as we did before with the entire study. The left of the

upper fields is a filtered version of the tree you can find on the left side of just about any window in the

AnyBody Modeling System. Rather than presenting all the objects of the model, this tree only comprises the

studies. If you expand a study, you will find its operations, which typically are: SetInitialConditions,

KinematicAnalysis, InverseDynamicAnalysis, and MuscleCalibrationAnalysis.

You pick an operation by clicking it once. This highlights its name, and you can now execute it with the Run

or Step buttons in the right hand field. The "Run" button starts the study and it will run until it comes to its

end or encounters an error. Once you press the run button, it changes its name to "Break", and pressing it

in that state breaks the current analysis process.

The "Step" button takes one step at a time, What a step is exactly depends a little on the type of operation.

For KinematicAnalysis, InverseDynamicAnalysis, and MuscleCalibrationAnalysis, a step is one time step of

the movement. For SetInitialConditions, a step is one of the several distinct operations necessary to put the

model into its initial state. We shall return to that subject in the next lesson.

The "Reset" button returns the model to its initial state after it has gone through a sequence of time steps.

You must press "Reset" before you can rerun the model.