"In which case, isn't comparing it to Simulink instead of Sympy a bit ... odd?" No, as it is not used as Sympy. Modelica is used to model physical systems in a

"In which case, isn't comparing it to Simulink instead of Sympy a bit ... odd?" No, as it is not used as Sympy. Modelica is used to model physical systems in a composable way with graphical representation of connections between components. Many people use Simulink for that, so this is why it is compared with it. Sympy is a nice project, but is applied in a different context, definitely not to model systems with thousands of equations in the industrial setting (that would be painful).