How to get a reference to object in another blueprint&

I have 2 BP and i want to use one spline from 1st blueprint in another one. I heard that it is possible by using cast to, but I m not sure what kind of object should i put in input of cast to.

If the blueprint is a specific type, you can use Get All Actors of Class and find the one you want.

Alternatively, if you’re placing them in the level, you can create a public variable that is a reference to the other. Then set that value in the details panel of the level editor.