| 摘要 |
PURPOSE:To provide the perspective drawing generating device which can generate a perspective drawing in a short time. CONSTITUTION:Before converting solid data for showing a solid to perspective drawing data, a virtual surfaces So (clip surface) being orthogonal in a position being extremely near a visual point with respect to a Z axis of a visual point coordinate system in which a visual point position is an origin is determined between the visual point and a plane of projection, a prescribed part positioned on the visual point side by the virtual surface So being a boundary in the solid is decided, and a clipping processing for deriving data for showing the solid in which the prescribed part is deleted from the solid data for showing the solid is executed. For instance, in the case a line P1-P2 and a line P3-P4 exist as lines for constituting the solid, whether each line and the virtual surface So intersect with each other or not is decided, an intersection Pc of the line P3-P4 and the virtual surface So is derived and the solid data for showing the line P3-P4 is changed. In such a way, since it will suffice that whether it intersects with a single clip face or not is decided, the processing time can be shortened. |
