Shrinkwrapping messy geometry

I’ve got some buildings made out in mixed ways, meaning they have many components, made with different techniques, they look good from the outside but are too messy on the inside to apply boolean operations (I want to cut holes into them). So my thought was using shrinkwrapping but I’m having problems with it.

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In the attached image I tried something simpler in preparation, a bunch of bricks: I’m only interested in the outside shape so I figured an easy way to eliminate the holes inside would be to do a shrinkwrap with a sphere. However it doesn’t seem to take on the brick edges shape. It does figure out the general shape of the pile, and does create some weird divisions & bumps, but doesn’t take on brick corners. I’ve tried subdividing more and more but doesn’t seem to work even with insane poly counts. Am I doing something obviously wrong?

PS: in the example i intentionally scaled the sphere too small so you can see the bricks under, initially i tried with it covering all.

Thank you for your patience!

The problem with shrinkwrap is that it will stick to the closest surface point. So it helps if the faces in the shrinkwrapped object roughly corresponds to the faces of the wrapped object. I made a bikini bottom with shrinkwrap once. To get it to look good I used two subsurf modifiers, and put the shrinkwrap modifier between them, and fiddled with which subsurf settings to see which worked best.

thank you!