Abstract: A pleated neckdown bag for lining a receptacle is disclosed wherein the bag is made of a flexible plastic film. The disclosed bag has one or more pleat portions (18) fixed at points around the mouth portion (26) of the bag to reduce the circumference of the mouth portion relative to the circumference of the body portion (14). The reduced circumference mouth portion of the neckdown bag can be fitted over a supporting receptacle. The top portion (12) of the bag is thereby more securely held to the support, and the mouth portion is more securely held in an open state, since the narrowed mouth portion of the bag can better engage a support such as the rim of a waste bin. Bag embodiments having flat and flat rectangular constructions, convenient for manufacture, storage, shipping, and dispensing, are also disclosed. Also disclosed is a tabbed neckdown bag embodiment with a tab (52) modifying means to advantageously modify stress and strain at and near the conjunction of a seam and mouth portion of a neckdown bag.

Abstract: In a computer aided design system, a geometric object is defined as a function, preferably a B-Spline, of a piecewise polynomial function. In order to make a local modification of said geometric object, a point of origin (P) is picked. A second point (P') is defined as a target point through which the modified function should pass. The move from the point of origin (P) to the target point (P') is transformed into a move, preferably a parallel shift, of the control points of the associated control polygons.