公开(公告)号：JPH05135138A

公开(公告)日：1993-06-01

申请号：JP31858291

申请日：1991-11-07

Applicant: IBM

Inventor： KURIYAMA SHIGERU ,  NAMIKATA HIROSHI ,  URANO NAOKI ,  SHIMIZU KAZUYA

IPC: G06F17/50 ,  G06T15/00 ,  G06T17/00

Abstract: PURPOSE: To attain the simple input of a curve expression, and to generate a polygonal patch having high continuity by generating a curved surface interpolating a curve by fusing a curve sweeping body across two stages. CONSTITUTION: This device is provided with a polygonal patch generator 8 which generates a curved surface expression based on a curve expression inputted from a coordinate inputting device and a multivariate coordinate inputted from an inputting device 3, and outputs it as polygonal patch data. Then, the data of a boundary curve are inputted through an editing means 4 which operates the generation and edition of the curve to the polygonal patch generator 8, and a free curved surface is generated as a curved surface interpolating each by fusing a curve sweeping body across two stages. That is, the data of the plural boundary curves are inputted to the polygonal patch generator 8, the curved surface is generated by sweeping each applied curve along the curve crossing the data by a sweeping means 23, and the curved surface is fused across two stages by fusing means 24 and 26 so that the free curved surface can be generated. The expression for the curved surface is defined based on the expression for the boundary of the curve.