In essence, RIB (Routing Information Base) is being built by various routing processes on the node, with information from routing protocols - like OSPF, IS-IS, BGP or even the static entries.
After out of all routes in RIB the best ones are selected, they are copied to FIB (Forwarding Information Base). The exact means vary from platform to platform. In general, it's either done by some IPC communication, internal network, or simply (in monolitic software solutions) as a copy (data or pointers) between tables.
So, RIB contains all the routes node is willing to keep and the information there is being used by the routing protocols. FIB is used by hardware to physically move the packets in and out of interfaces. Hardware can keep forwarding based on the FIB contents, while RIB is being updated/etc.
Take a look here for starters: http://blog.ipspace.net/2010/09/ribs-and-fibs.html and then - for example - dig deeper into http://networkstatic.net/juniper-and-cisco-comparisons-of-rib-lib-fib-and-lfib-tables/ for more detailed RIB/FIB/LFIB illustration.
A granular view of the situation is required.' sounds a little rude. It's community portal, if you
require something maybe you should look for commercial ways of gaining this knowledge.