Shaped carton CAD design process (in)

3 splicing technology

The basic idea of ​​the splicing technique is to compose complex objects with simple regular-shaped geometry. The splicing algorithm differs greatly depending on the entity representation and data structure chosen for each system. From a topological point of view, the merging operation classifies the points of the participating objects and finds the set of points that make up the result of the operation. Shaped cassettes are flat graphics that are simpler than three-dimensional solids.

The splicing technique used in this paper mainly involves the editing function of the cassette piece parts. The user can carry out positioning and position the cassette piece parts through axisymmetric transformation, centric symmetry transformation, mirroring, rotation, shifting, etc., by copying, copying, deleting, and amplifying. , zoom out, etc.

4 box parts

1) The composition and division of the box parts

A box piece part is a closed plane pattern enclosed by a strip edge, and the lines constituting the box piece part can be divided into border lines and non-boundary lines, and the border lines are further divided into connectable edges and non-connectable edges. All of the boundary lines constitute the closed outer boundary of the cassette parts, and only the connectable sides can be shared by the two cassette parts to form the connecting parts of the two cassette parts. When the box piece is not connected to the box piece, its periphery is a single solid line representing the contour cutting line; after the box piece is inserted, the common edges of the two box piece parts correspond to the indentation lines in the actual box piece ( As shown in Figure 3 (a), (b) shallow solid side).

Each individual face of the Carton can be divided into a box piece. The basic principle for splitting a box piece into a box piece is that each individual plane after the box is split into a box piece, for some structures. There are two or more surfaces that are closely related, and it is also possible to combine them into a box-type part to be considered, as in Fig. 4(a) (see previous page). The main swinging wing and the tongue, due to the latch between the two parts The structure has strict limitations on the dimensions of the structure. Therefore, it can be divided into a box piece part. Figure 4(a) can also be divided into two separate parts as shown in Figure 4(b), but it is generally divided according to (a). 4(c) The two faces of the window are considered to be the same cassette part because of the window opening. According to this rule, the functional surface of the carton can be disassembled, and the disassembled cassette parts can be placed in the part library to be called directly during the design of the cassette. When creating a cassette library, care should be taken that the cassette part must be parametric, ie the geometric parameters that make up the cassette part must be adjusted automatically as needed.

(to be continued)