Strait surface projection Drape alike, possible?

Hello, I have a structure made of polysurfaces. Using rhino5 is it possible to “project a surface” on top of the existing structure, so I would get a Drape-alike affect, only with strait surfaces and not bumpy ones like I would be getting using the Drape tool?

I would like to get one polysurface / mesh that roughly emulate the general shape of the multi-polysurface structure I already have.
or, is there a way to straiten the bumpy drape I got by using Drape tool?
Thanks!