Rigid joints: These are the joints which are capable of transferring axial forces as well as moment. For example Joints provided in the roof slabs.
Pin Joints: These joints are capable of transferring axial forces but can not transfer moment. For example links of chain in cycle.
If body have no joints it is hard to break because there is no plane of failure.
Basic Difference between Pin and Rigid joints:
In pin joints there is relative rotations between two members whereas in rigid joints it is not possible.