Why do we have to typecast NewtonContactJointGetFirstContact

[Van]

Why do we have to typecast NewtonContactJointGetFirstContact() and NewtonContactJointGetNextContact() returned data?

[Julio Jerez]

Because it return a pointer to a node in a container. you can see the containre in the dContianer Library,

The node let you muve to next node and read teh data it contain, bu the are templates and there is not way to pass tha back in a C inteface.
and if it was possible the type isself is of not relevant used, and will generate a proliferation fo meaninless data types.