Papers by Keyword: NURBS Curve

Abstract: The article briefly deals with a algorithm of adaptive interpolation for NURBS curve which NURBS curve reache any point, while, the feed rate can keep costant as during the whole interpolation process. The interpolation of NURBS curve should be finished. The simulation results show that the algorithm is correct; it is consistent with a NURBS curve interpolation requirements.

Abstract: In hand-drawn graphics modeling method, the input to the system free hand draw curve is the first step in modeling. Effective fitting the curve of the input is the key to modeling effect is good or bad. For noise, free shape features of hand-painted curve, presents a method of using NURBS curve fitting of hand-painted curves. Experiments show that using NURBS hand-drawn curve fitting, the fitting effect is good, easy to modify, for later use of curve, not only can be used in hand-painted curve modeling system, can also be applied to the mainstream way of WIMP modeling system.

Abstract: In this paper, firstly the characteristics and discrete mathematics method of Nurbs curve were studied in-depth, and a NC processing method based on De Boor-Cox algorithm was presented. Then, dedicated data-processing software for NC system was developed with VC++ 6.0. This software has been well applied in practice production, and the production efficiency is improved as well.

Abstract: The NURBS curve interpolation algorithm based on parabolic interpolation error and the first-order Taylor expansion interpolation algorithm is proposed to improve part surface quality and chord error of NURBS curve interpolation algorithm. The part surface quality is improved effectively by the parabolic interpolation algorithm in the conduction that the previous point, the current point and the next point which was computed by the first order Taylor expansion interpolation algorithm were known. The effectiveness of this algorithm is proved by the NURBS curve interpolation simulation.

Abstract: This paper converts a NURBS curve to piecewise rational Bézier curves by knot insertion algorithm, and then discusses the algorithm of continuous connection of NURBS curves. Meanwhile, explores the method to keep the same shape of the NURBS curves after connecting through the point translation and vector rotation theory. Finally, gives an instance to verify the validity of the algorithm.

Abstract: This paper proposes a real-time coplanar Non-Uniform Rational B-Spline (NURBS) curves fitting in CAD/CAM system to improve the fitting quality and reduce the calculation effort. The real-time NURBS curve fitting process consists of (1) the reading discrete points, (2) curve segmentation and data reshaping, (3) curve fitting, and (4) local and global modulation. According to the simulation and experimental results, the proposed approach certainly raises the fitting quality and the efficiency of calculation.

Abstract: To solve the difficulty and low efficiency of three-dimensional reconstruction of complex spatial form bent tube, a stereo vision method with NURBS curve to achieve three-dimensional reconstruction of bent tube is presented. This method first extracts central axis and the edge line of bent tube by the grayscale image, and the outer diameter of bent tube is calculated through the edge line extracted. On the premise of affine camera model, NURBS curve has been chosen as the primitive of reconstruction, and by using its affine invariance, according to the principle of binocular vision, the central axis of bent tube is reconstructed through reconstructing the control points. Finally, the three-dimensional model of bent tube is reconstructed by three-dimensional modeling technique. Experimental results show that, relative to the traditional methods, this method makes a big improvement on the efficiency and accuracy of three-dimensional reconstruction of bent tube.

Abstract: Determining regularity and convexity of NURBS curves is necessary in computer aided geometric design. In this paper, the problems above are converted to the questions related to polynomials. Then based on properties of algebraic equations and isolation theorem of roots, a simple and practical method for determining those geometric properties of NURBS curves is put forward. Compared with traditional method it will save us much computation

Abstract: Although the chord height error might be ensured, the adaptive algorithm of the NURBS curve circular interpolation feed rate is still likely to result in the speed fluctuation which is not in accordance with given acceleration or deceleration rules. On the foundation of the analytic principle of the NURBS curve circular interpolation, a kind of interpolating algorithm based on the NURBS curve continuous small segments of S-shaped acceleration and deceleration is presented. And considering the chord height error, the variable step and feed rate can be effectively combined to make a better estimation. The simulation results on real examples show that the method not only simplifies the complicated calculation of curve interpolation process, simultaneously improves the speed of Motion Smoothing Implementation for NURBS curve interpolation, but also ensures the interpolation precision. The algorithm can be commonly applied in real manufacturing for high-speed and high-precision curve process.

Abstract: In this paper, a design of 2-3-dimension transformation for helmet with Rhino Developer Platform is presented. In the design, helmet from two-dimension to three-dimension and from three-dimension to two-dimension have been realized. After transformation the two-dimension helmet pieces and the three-dimension helmet pieces content their area, length of boundary lines and position of mesh points on helmet pieces approximately equal. This design is controlled and realized by VC++ program. At last, the visual effect of transformation is provided in Rhino Operating Platform and meanwhile its implementation is validated.