三维CAD模型的几种表达方法说明 构造型立体几何表达法 边界表达法 参数表达法 单元表达法-3D CAD model of the expression of several tectonic descr iption of a three-dimensional geometric expression - border parameters Expressions Expressions Expressions unit

在CAD中，用分段三次B样条来表达自由曲线是很理想的，为此，采用三次B样条曲线来拟合这条折线. ... 其中， 3d.gif (1661 bytes) ，确定了系数a、b、c，相应地就确定了拟合函数. 3)确定型值点求出拟合函数后，取点Pk((1/2)l，yp)作为型值点. ... -in CAD, and cubic B-spline curves to the freedom of expression would be the ideal, for cubic B-spline cur

EWDraw 3D is a powerful vector graphics ActiveX for 3D and 2D visualisation and animation. You can use it for CAD,CAM,GIS and others. The EWDraw is based on Open CASCADE geometric kernel and openGL. The component is realized as a run-time Windows 3