| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device for setting patch front and rear faces which quickly pick up a reference patch as a reference for setting front and rear faces of each patch and prevent a computer program for thin picking-up from being made complicated. SOLUTION: With respect to the method which sets front and rear faces of plural patches constituting a three-dimensional shape O, reference patch candidates P1 , P2 ,... having the maximum coordinate value on the (z) coordinate are selected, and respective unit normal vectors of these reference patch candidates P1 , P2 ,... are obtained. The patch P1 whose absolute value of the (z) coordinate component in the unit normal vector is maximum is picked up as the reference patch. Next, the order of apexes of the reference patch P1 is so set that the (z) coordinate component in the normal vector of this reference patch P1 is positive. Orders of apexes of all remaining patches are set based on the reference patch P1 . |
