A HUMAN FRIENDLY APPROACH TO SURFACE GENERATION

随着客户需求的日益多样化和产品生命周期的缩短，初步设计变得越来越重要，因此，设计师希望尽可能自由地绘制曲线和曲面的愿望正在迅速增长。但传统的曲线曲面生成方法都是用控制点来表示几何图形，因此曲线曲面只能间接绘制。因此，很难画出一个曲线或一个表面，因为一个人的愿望，一旦画出来，它是非常难以修改它。因此，在这项工作中，一种方法是developoeped允许设计师生成和修改的几何形状非常自由，如果他或她是画一张纸上的草图，使用这样的设备作为鼠标或三维测量设备。1994年提出了一种曲线生成方法，并将其推广到三维曲面生成。在1995年，基于这些结果和检查，改进了三维表面生成方法，并详细描述了这些方法以供用户使用。这些二维和三维几何生成方法通过移动平均法平滑鼠标或三维测量设备的轨迹，并从这些曲线或表面提取特征点。利用Bezier曲线或其扫掠曲线生成所需的二维或三维几何图形，如果与虚拟现实设备相结合，可以以非常交互的方式灵活、自由地生成和修改几何图形。

With the increasing diversity of customer's requirements and shortening of life cycles of products, the preliminary design becomes more and more important, and therefore the desire on the part of a designer to draw a curve and a surface as freely as he or she wishes is growing rapidly. But the conventional methods of curve or surface generation use control points to represent a geometry so that a curve or a surface can only be drawn indirectly. Thus, it is difficult to draw a curve or a surface as one desires and once drawn it is extremely difficult to modify it.Therefore, in this work, a method is develoeped which permits a designer to generate and modify a geometry very freely as if he or she is drawing a sketch on a sheet of paper, using such a device as a mouse or a three dimensional measuring device. No mathematical knowledge about control points is necessary in this method.In 1994, a curve generation method was developed and it was extended to 3 dimensional surface generation. In 1995, based upon these results and examinations, the 3 dimensional surface generation method was improved, and the methods were described in details for instructions for users.These 2 and 3 dimensional geometry generation methods smooths the trajectories of a mouse or a 3 dimensional measuring device by a moving average method and points of features are extracted from these curves or surfaces. And Bezier curves or their sweep curves are applied to generate a desired 2 or 3 dimensional geometries.If coupled with Virtual Reality devices, the geometry can be generated and modified flexibly and freely in a very interactive manner.