Can I make this surface using Breps not meshes?

Hi All,

I am new to grasshopper and am traditionally a solid modeler so my knowledge/workflow is coming from that direction. Ideally, I want to use grasshopper to make parts that I can then take into a solid modelling program and work with them there so I’d like to steer clear of meshes and stick to surfaces and breps. But as I say, I’m new to grasshopper so not sure if this is possible!

Anyway here is a specific example. I am trying to create something like this without meshes. Is it possible? What should I be using? (Not looking for code specifics just a direction).

I have tried extruding the polylines to interect the initial surface but it’s not clean and I don’t know how to round the edges so I get soft cutouts. Thanks (20.8 KB)