Create a bonus hit spot (help!)

I am 100% new to unreal, and I am trying to implement a bonus hit location when farming for resources (wood, rocks, dirt, sand etc). I want it so that when i start hitting the resource model a random “hit spot” (an indicator) will randomly appear on a certain area of the resource model, and it will add extra 5% resource to inventory if hit within a certain random time (1-2 seconds), they ot will not register until resurce model is hit 2 more times

example:

I suggest you can manually mark a set of points on the object in question. You can have more points than needed and randomly chose some of them.

Then, when you get the hit location you compare with the distance to each point from the set.

If the hit is really, really close to one of the points add the 5% increase (and remove the point from the set I guess)

You can also look into “Sockets” to mark pre-defined spots on a static mesh, or you can use scene components, or colliders within your blueprint to mark off these areas.