| 摘要 |
PURPOSE:To make it unnecessary to use a sectioning Z buffer by constituting clipping processing of two steps and removing a graphic element arranged on the visual point side in accordance with the initial clipping processing. CONSTITUTION:When a cutting plane corresponding to a world coordinate system is specified to a solid model, the world coordinate system is rotated in the 1st processing process P1 so that a vector drawn from the origin of the world coordinate system vertically to its cutting plane coincides with the Z axis e.g., so that the cutting plane is made parallel with the XY plane to be available as the reference face of clipping processing. In the 1st processing process P1, the cutting plane is set up on the position parallel with the XY plane. In the 2nd processing process P2, clipping processing is executed based upon the rotated cutting plane to remove the graphic element positioned on the visual point side observed from the cutting plane. Consequently, the cutting plane of a solid model can be displayed without using the sectioning Z buffer. |
