If the pieces are > 8' long then you must manually edit those SketchUp components and split them into several parts.
You'd have to do it to the DXF files too [in CAD] ??
There's nothing that's perfect - as far as I know ?
Does CutListOptomizer do it [orthogonal?] ?
Youtube Video
https://www.mynesting.com/
might process DXFs of the parts ?
https://www.maxcutsoftware.com/
??
I'd expect that some CNC software does that optimizing as a later step...
But these will assume orthogonal too ?
With complex curved shapes like your ribs, then manually locating and rotating them onto a simple 4x8' sheet 'template' underlay component, locked in place, is still likely to be your best solution...