| 摘要 |
PURPOSE: To provide a simple device for processing the crossing of a coplanar object and a picking volume by calculating whether or not a plane including a displayed object crosses against the edge of the picking volume and calculating whether or not the object and the picking volume cross against each other at the time of judging that it does. CONSTITUTION: The object is divided in a mosaic shape to plural basic solid bodies on a coplane for which the respective basic solid bodies are defined by a set of vertexes in a step 550 and the basic solid body is selected from the object in the step 560. Whether or not the basic solid body is entirely or partially positioned inside the picking volume is decided in the step 570, and when it is not positioned, whether or not it is the last basic solid body of the object is judged in the step 580. When it is not the last, a processing is returned to the step 560 so as to select the next basic solid body. In the step 570, at the time of crossing against the picking volume, the object is received in the step 595. |
