The chain consisting of joints and coordinate transforms may form a loop, also called closed kinematic loop. In order to handle such loops correctly, special joints from CutJoints library are used. In order to make possible for the user to specify valid initial state for such mechanical system, a hint can be given to the translator, and a joint with state variable is selected. The parameter startValueFixed is set to true for this purpose. The example below shows a system with a single closed kinematic loop. The upper bar (a cylinder with small radius) is fixed; three other bars are connected by revolute joints. The whole system behaves like a pendulum.
The Modelica code of the PendulumLoop2D model with these attributes is represented below