| 摘要 |
PURPOSE:To decide the inside and the outside, and the size with high accuracy and at a high speed even in the case of a curved surface piece having a free curve in the boundary by constituting a three-dimensional vector of a line integral of a directed border line of the curved surface piece, and deciding the inside and the outside of the curved surface piece by using its direction. CONSTITUTION:An aggregation of a straight line and a free curve for constituting a boundary of a curved surface piece is derived. One element of its aggregation is selected and three line integrals related to (x) - (z) are derived and accumulated in a storage device. Subsequently, with respect to all other elements, the same processing is executed, and the line integral is stored in the storage device. An average normal vector of this curved surface is determined as a vector having the sum total of each line integral in the (x) - (z) components, and its component and a size of the vector are calculated and stored in the storage device. By utilizing a fact that its average normal vector is turned to the outside of a solid, the inside and the outside of curved surface piece are decided. Also, by using the size of the average normal vector of the curved surface piece, it is set as a decision reference of the size of the curved surface piece. |
