You can also call blueprint variables from another blueprint by using a way that I only just realised, although I can’t believe I didn’t. when you need to access the variable, simply put “Cast To [BluePrint Name]”, and drag out the "As [BluePrint Name Casting - Child Parent] node and type the name of the variable. This will allow you to affect and search for the other BluePrints’ variable. If my description wasn’t clear, I have included the link to a tutorial on this subject.
