Update 24-May-2020:
I post the single filament case fusion360 model (Galaxy Note 10+ cover MMU2 All Resin v4.f3d).

This is a case for Samsung Galaxy Note 10+.
Can be printed by single filament, or PETG+FLEX using MMU2S on Prusa i3 mk3s
Files description:

1. Single filament:
   Single_Cover.stl - stl for printing with single filament (PETG)

2. Multifilament:
   MMU2_BackCover.stl - stl for back side of cover (PETG)
   MMU2_Black.stl - stl for flex sides of cover (REC Black rubber filament)
   MMU2_Cover.3mf - PrusaSlicer project for multymaterial printing.

   I made special geometries since PETG and Rubber have weak adgesion between them. You can see them in MMU2_BackCover.stl and MMU2_Black.stl files.