About rigid Link!!

[amaniish]

I am having hard time understanding rigid Link and how does it work!!
Like, I added a rigid Link at the top of pier to connect c.g. pier cap and pier together, so it means we cannot apply load to c.g. of pier and expect response ,or if we apply at force at any node of pier cap , the force through slave node(c.g. of pier cap) will get transferred to pier or not?
Can anyone explain, providing a short example to explain this!