"draping" a surface over a series of solids

I'm trying to create a shell which will sit over a series of solids and a few key polyline set curves. Is there a way of draping a surface/shell with say an offset of 10mm from all respective solids and to "stick" to the polylines? I then need to be able to push /pull the surface in places to fit either more elements under the skin or modify it to smooth out a bump or trough.

It's basically some bodywork which I need to form based on a few curves for aerodynamics and over the chassis/wheels/motor and be able to adjust for clearance or airflow - its for a youth STEM challenge so not commercial. Or would it be easier to export the various parts of the car already designed as STL or similar into another bit of software to form the bodywork?