Consider that one creates a library feature (say, a sketch with construction lines and points representing a mounting hole pattern) and uses equations to drive the dimensions on the sketch. When one imports that library feature into another part, the equations are also imported, kind of... Meaning the global variable name from the original part file appears in the `Value/Equation' field of the part file which hosts the library feature. It appears in red, however (see attached), and also always gives an error when one tries to close the 'Equations' window (also see attached). Furthermore, the 'Evaluates to' field is empty.
This approach has worked for me so far. I can't help but to think that there is a better practice here, of which I'm currently not aware. Any comments and suggestions are greatly appreciated.
I don't know if you've figured this one out yet, but here's what I know (or think I know).
It seems from my experience that if you want to use a global variable, like "major_hole_half_pitch" that variable has to already exist in the file you're dragging the library feature into. Global variables will reattach to values of the same name but I don't think it'll create ones that don't already exist in the part.