Hi, it looks like this struct is from RigVM Plugin. I’ve never used this plugin, but it has it’s own blueprints, so maybe those structs are used there.
I can’t even find those types directly in C++, so I don’t think they can be used in normal BPs.
As for calculating sum of an array I assume you can do it in ForLoop or ForEachLoop. Or you are looking for any special way?