The tuck-type folding process is more complicated than the simple one because of its essentially 3D aspect. In fact, in a general case, the two surfaces between which some part of an airbag is inserted should not only be pushed "up" and "down," but also to the sides in order to avoid intersections. This side-pushing effect increases the width and the surface of the airbag considerably. Moreover, in most cases this is not necessary, because of a kind of "convergent" shape of parts being pushed inside. Therefore, in the present version of the folder, the tucking operator does not increase the width of the outer layers of the airbag. It is up to you to check for possible surface intersections in the cases where the width of the moved part is equal (or almost equal) to the width of the outer layer.
The following section focuses on shape changes obtained during tuck folding in the down-up direction.