Select geometry based on true/false values

i want to select the field line curves based on true false values so I can trim them with different lengths later on.
how to change this boolean output to a geometry input for the trim tree node?

MAIN MAG (43.7 KB)
MAG field lines on site.3dm (324.2 KB)

I hope I’m not understanding this wrong. But you can just use the dispatch component to actually dispatch the curves instead of dispatching your True/False pattern. Is this what you want to do?

no actually i want to take the dispatched curves and then put it in to evaluate length so I can have separate trim values for each type of curve (red / green)

I’m not at a computer right now. But you should be able to just plug the two dispatch outputs from the setup I’ve posted each to a separate evaluate component with it’s respective value and then that should be what you’re looking for?!
I’m sorry but I don’t really see the problem.

unable to read files- need Rhino V6 file.

What’s the bigger idea?