There are a few challenges…
The first one is remeshing your object with TriRemesh so it has colinear edges like your polysurface. This failed at the real size of your building and I needed to scale it down to get it to work.
The vertices on the outermost convex edges can be set as anchors. In theory a net would also slide over those edges… The top and bottom side of the mesh can be ignored to save some time.
We’d be done, if it wasn’t for the collisions. In order to have a somewhat useful result, the mesh and the collider need to be relatively dense meshes, otherwise the edges aren’t crisp. It would be easier if the collider was a sphere. The denser the mesh, the more precise is the result but also the longer it takes.
I get the best result by moving the collider solid incrementally towards its final position. In this case I scaled it from 0.96 to 1 in 0.002 incremets with a slider. I changed the slider value with a keyboard shortcut. After having done this twice, I realized I could use a counter that I think Daniel Piker posted a while ago. It needs to be stopped manually but it’s still a lot bettr than pressing a button repetively.
I also increased the mesh density. The star shape is still problematic.
shrinkwrap_building.gh (8.7 MB)