Abstract: This invention relates to a method of creating a complex curved surface, which includes a step of from data specifying three-dimensional curved surfaces (12a, 12b). Data is input specifying a reference line of intersection (CL.sub.i) on the XY plane (10) and a rule for generating lines of intersection on the XY plane on the basis of the above-mentioned reference line of intersection. Also a range (SCR1, SCR2) is specified for each of the three-dimensional curved surfaces (12a, 12b) to obtain a section curve on the three-dimensional curved surface, for a section corresponding to one of the lines of intersection. The method includes obtaining first and second section curves (13a', 13b') in the range (SCR 1, SCR2) when first and second three-dimensional curved surfaces (12a, 12b) are cut by a section whose line of intersection with the XY plane is an i-th line of intersection (CL.sub.i). Then, a point of intersection (CR.sub.i) between the two section curves (13a', 13b') is obtained.

Abstract: The invention relates to a complex curved surface creation method for generating a curved surface in which roundness (ARC) of a radius R is provided at a portion where a first curve (11) approximated by straight lines on a first three-dimensional curved surface (1) intersects a second curve (12) approximated by straight lines on a second three-dimensional curved surface (2). Among line segments (P.sub.i P.sub.i-1) constituting the first curve (11) and line segments (P.sub.j P.sub.j+1) constituting the second curve (12), one line segment is selected from each curve in the order of their nearness to a point of intersection (P.sub.0) of the two curves. Next, it is determined whether a circular arc of radius R to which both of the line segments (P.sub.i P.sub.i-1, P.sub.j P.sub.j+1) are tangent exists. If such a circular arc does exist, the circular arc is inserted at the portion where the two curves intersect, thereby rounding the intersection.

Abstract: This invention relates to a method of creating a complex curved surface (100) by combining at least first and second three-dimensional curved surfaces (101, 102), which method includes a step of inputting data for specifying first and second three-dimensional curved surfaces (101, 102), a step of obtaining coordinates of a j-th point Q(i,j) along an i-th path L.sub.

Abstract: The invention relates to a method of creating a complex curved surface (CPS) comprising at least two three-dimensional curved surfaces (10a, 10b), particularly a method of creating a complex curved surface in which roundness is provided at a portion where first and second curved surfaces intersect. In the curved surface creation method, rounding is performed by obtaining normal vectors V.sub.1, V.sub.2 of first and second curved surfaces (10a, 10b) at a point of intersection P.sub.0 of first and second section curves (11, 12) obtained when the first and second curved surfaces are cut by a section (13) perpendicular to the XY plane, calculating an angle .theta. defined by V.sub.1 .times.V.sub.2 and a normal vector V of the section (13), calculating R' in accordance with the equationR'=(1+1/.vertline.cos.theta..vertline.).multidot.R/2when roundness of radius R is commanded, and inserting a circular arc of radius R' at the portion where the first and second curved surfaces intersect.

Abstract: This invention relates to a complex curved surface creation method for creating a complex curved surface (201) composed of at least two three-dimensional curved surfaces (201a, 201b, 201c). The complex curve surface creation method comprises a first step of inputting data for specifying each of the three-dimensional curved surfaces (201a-201cand inputting data specifying one line of intersection (CLi) on a predetermined plane e.g. an X-Y plane (203) as well as a rule for specifying a number of lines of intersection on the predetermined plane on the basis of the line of intersection, a second step of finding a section curve (SCi) of the complex curved surface (201) based on a section (202) which has an i-th line of intersection, among the number of lines of intersection, as its line of intersection with the predetermined plane (203), and a third step of specifying the complex curved surface (201) by assembling the section curves (SCi; i=1, 2, 3, . . .