Up front, firstly, if you could draw your object, with the proper radii, and then use a simple extrusion, it would be good to do so.
Without special plugins, I have modeled bends by using a transform/flow along curve.
Generally, I create my shape, create a source and destination bend curve (selected), and have Rhino wrap the part around the bend. The bend radius must be appropriate. The lengths must be the same, but for no plug-in, it works. I usually color these curves magenta so they stand out against my blue curves.
Though, you have some pretty tight box-style bends. From the centers of the petal-like objects, I might radially split the object ( to the center of the triangles and pentagons), make the bends, and then union the result.
The odd thing about doing it this way, to some degreee, where you have distortions, you likely will in real life, though not that it was done with Finite-Element.
Because there are often more than one solution, you could also clip the inner petals, and then create curves which could be extruded to create only the the raidius area, and then join them. The curves would have to be rotated in three dimensions, to do an extrusion. The edge of the clipped edge could be selected for an extrusion Direction (option) to make sure that it is true to the edge, and not Euclidian (xyz) space.