Hi
The geometry collection component is the place that provide various ways to get or set information on bones/items
General use case, is to use a trace in a blueprint that tells you which part was hit by the trace and get the hit item index to query information ( like mass / extend for example ) or to apply strain or breaking velocity
Not all information have getters / setters though
To get the dynamic transform ( during simulation ) the best way right now would be to use the socket functions since each piece of a geometry collection is exposed as a socket
If you only need the rest transform ( before break ) you can use GetLocalRestTransforms
I hope this helps