摘要：Abstract. The OpenNURBS initiative provides CAD/CAM/CAE and computer graphics software developers the tools to accurately transfer 3D geometry between applications. The OpenNURBS C++ source code is clean and fairly simple. The OpenNURBS Toolkit is intended for use by C++ and .NET programmers. The toolkit includes complete source code to create a library that will read and write 3dm files. OpenCASCADE providing services for 3D surface and solid modeling, CAD data exchange, and visulization. Most 阅读全文

摘要：Abstract. A root-finding algorithm is a numerical method, or algorithm, for finding a value x such that f(x)=0, for a given function f. Such an x is called a root of the function f. In OpenCASCADE math package, implemente Newton-Raphson method to find the root for a function. The algorithm can be used for finding the extrema value for curve or surface, .i.e Point Inversion, find the parameter for a point on the curve or surface. The paper focus on the usage of OpenCASCADE method and its applicat 阅读全文

摘要：Abstract. DWG is a file format created in the 70’s for the emerging CAD applications. Currently it is the native file format of AutoCAD, a proprietary CAD program developed by Autodesk. Libredwg is a free C library to read and write DWG files. This program is part of GNU project, released under the aegis of GNU. The paper focus on the usage of Libredwg, and use the Libredwg to read a DWG file and output the entities of the DWG to Tcl script for OpenCASCADE Draw Test Harness visualization. Key 阅读全文

摘要：Abstract. The conic sections and circles play a fundamental role in CAD/CAM applications. Undoubtedly one of the greatest advantages of NURBS is their capability of precisely representing conic sections and circles, as well as free-form curves and surfaces. We assume a knowledge of conics and circles, the purpose of this paper is to study them in the framework of their representation as NURBS curves. Key Words. OpenCASCADE, Conic Curves, Circle, Convert, BSpline Curve 阅读全文

摘要：Abstract. Rational Bezier Curve can represent conic curves such as circle, ellipse, hyperbola, .etc. But how to convert a conic curve to BSpline curve is still question, i.e. Represent a conic curve in BSpline form. The key point of Hyperbola conversion is to calculate the 2nd pole and its weight factor. The paper focus on the hyperbola convert to the BSpline curves. Key Words. OpenCASCADE, Convert, Hyperbola, BSplineCurve, Conic Curve 阅读全文

摘要：Abstract. Rational Bezier Curve can represent conic curves such as circle, ellipse, hyperbola, .etc. But how to convert a conic curve to BSpline curve is still question, i.e. Represent a conic curve in BSpline form. Parabola curve is the most simple conic curve, that the parabola does not require rational functions. Let’s begin from the simplest one... Key Words. OpenCASCADE, Convert, Parabola, BSplineCurve, Conic Curve 阅读全文

摘要：Abstract. When you are familiar with OpenCASCADE on Windows, you should try it on Linux operating system, because of Debian is also open source like OpenCASCADE. The paper is focus on how to building the OpenCASCADE on Debian. Key Words. OpenCASCADE, Linux, Debian, Building 阅读全文

摘要：Abstract. Use the Draw Test Harness to test the performance of OpenCASCADE by Tcl scripts. From the test result, you will check whether the OpenCASCADE meet your need. Key Words. OpenCASCADE, Performance Test, Draw Test Harness, Tcl/Tk, 性能测试 阅读全文

摘要：Abstract. The color scale is a specialized label object that displays a color map and an accompanying numerical scale for color mapped or contour data plots. As the geometry modeling kernel of SALOME, OpenCASCADE provides the color scale function. The paper focus on the usage of color scale in OpenCASCADE. Key Words. OpenCASCADE, Color Scale, 应力云图, 颜色映射表 阅读全文

摘要：Abstract. Although polynomials offer many advantages, there exist a number of important curve and surface types which cannot be represented precisely using polynomials, e.g., circles, ellipses, hyperbolas, cylinders, cones, spheres, etc. So we introduce the concepts of rational curves and homogeneous coordinates to solve the problem. To understand rational curves in a homogenous coordinate system is more straightforward. If you define irrational Bezier curves in 4D space and then project them ba 阅读全文

摘要：Abstract. Numerical integration is the approximate computation of an integral using numerical techniques. The numerical computation of an integral is sometimes called quadrature. The most straightforward numerical integration technique uses the Newton-Cotes formulas(also called quadrature formulas), which approximate a function tabulated sequence of regularly spaced intervals by various degree polynomials. If the functions are known analytically instead of being tabulated at equally spaced inter 阅读全文

摘要：Abstract. The natural parametric equations of a curve are parametric equations that represent the curve in terms of a coordinate-independent parameter, generally arc length s, instead of an arbitray variable like t or u. According to the natural equations, the curve length is the integration of the curve parametric equation’s derivation. So the core algorithm for curve length calculation is the numerical integration method. OpenCASCADE use Gauss-Legendre to calculate the integration for single v 阅读全文

摘要：Abstract. OpenCascade uses advanced text rendering powered by FTGL library. The FreeType provides vector text rendering, as a result the text can be rotated and zoomed without quality loss. FreeType also support unicode charset. The paper focus on the Chinese Text rendering. Key Words. OpenCascade, FreeType, Chinese Text, 中文汉字, Unicode 阅读全文