| 摘要 |
The original planar shape or developed shape of a product to be manufactured by bending is determined using a computer-aided design system. An operator operates a tablet unit to prepare, first and second projection drawings of, e.g., an L-shaped product, projected onto two planes parallel to the outside of first and second sides of the product, with a bending line in common. The computer-aided design system displays the first and second projection drawings on a display screen in accordance with shape data which defines the two projection drawings (S1). In response to the operator picking two vertices of each projection drawing on the side of the bending line using the tablet unit (S2, S3), the processor calculates distances of movement in the X- and Y-axis directions and the rotational angle of the second projection drawing required for the alignment of the two sets of vertices (S5). Based on these calculated values and the amount of expansion or contraction of the product material accompanying the bending work, calculated in accordance with input data indicative of the thickness, bending angle, and bending direction, the processor prepares shape data indicative of the product shape prior to bending and causes the developed product shape to be displayed on the display screen (7).
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