5.8.2.4.7. Breakable Joint

This example considers a breakable joint. A breakable joint is a joint that cannot withstand an internal force higher than a given value. To create a breakable joint:

Get the joint by inserting a command on a planar joint:
```
joint=CS_Joint.Find(_jid)
```
Create a joint condition to prescribe zero velocity on the two translational degrees of freedom:
```
driver=CS_Driver(Joint,System.Array[int]([0,1]),CS_Driver.E_MotionType.E_Velocity)
```

Define the value of the velocity, then retrieve the time measure:

Env=CS_Environment.GetDefault()
Sys=Env.System
(ret,found,time)=Sys.FindOrCreateInternalMeasure(CS_Measure.E_MeasureType.E_Time)

Define the time as variable, and use constant values for the two components:
```
driver.SetInputMeasure(time)
driver.SetConstantValues(System.Array[float]([0.,0.]))
```
Next, make the driver only active if the force in the joint is less than a maximum threshold of 3N. To do that, create a Condition based on the joint force measure norm.
Retrieve the force on the joint:
```
force=joint.GetForce()
```
Create a component measure, that is the norm 2 of the force. To be computed at each time step, this measure has to be added to the system.
```
norm=CS_ComponentMeasure(force,-2)
Sys.AddMeasure(norm)
```

Now, create the condition and assign it to the driver:

cond=CS_Condition(CS_Condition.E_ConditionType.E_LessThan,norm,3.0)
driver.Condition=cond

Finally, add the driver to the environment:
```
Env.Drivers.Add(driver)
```