S = shell (S, F, T) removes the faces of S indexed by F, as solid.Shape.faces returns them, and hollows what is left to walls T millimetres thick, as a box, a cup or an enclosure is made. The walls grow inwards, so the outside of the part keeps its size and the inner corners stay sharp. With F empty no face is removed and the result is a closed shell around a sealed cavity.

S = shell (…, 'Outward', true) grows the walls outwards instead, so the inside keeps the size and shape of S and the outside grows by T: the way to make a box that a part of the shape of S fits into. It is false by default.

S = shell (…, 'Thickness', {FACES, T2, …}) gives the faces indexed by FACES walls T2 thick instead of T, and so on for every pair in the cell array: a thicker floor, a thinner lid. The faces come from solid.Shape.faces, none may be opened, and none may be given two thicknesses:

 ## A box of 2 walls with a floor 4 thick, open at the top
 B = solid.box (60, 40, 30);
 B = shell (B, faces (B, 'Normal', [0, 0, 1]), 2, ...
            'Thickness', {faces(B, 'Normal', [0, 0, -1]), 4});

Walls too thick for the shape, which would meet in the middle, cannot be built and raise an error.

 ## An open box of 1 mm walls
 B = solid.box (10, 20, 30);
 B = shell (B, faces (B, 'Normal', [0, 0, 1]), 1);
 volume (B)
 ⇒ 1824.0

See also: solid.Shape.faces

Source Code: solid.Shape