共查询到19条相似文献，搜索用时 109 毫秒
1.
2.
高鹰 《郧阳师范高等专科学校学报》1999,(3)
本文在Catmull-Rom样条曲面的基础上提出了构造及解决了基面为（G1,K=1）Catmull-Rom或（G2,K=2）Catmull-Rom样条曲面的五次（G2连续）及三次（G1连续）超限插值过渡曲面的法． 相似文献
3.
为了平滑曲面拼接中出现的奇点（或奇线），章提供一种割补法，即在奇线附近割去一小块曲面，同时补充一过渡曲面片，使曲面整体具有GC^1连续，并给出过渡曲面和原曲面接触程度和割补面积的计算方法。 相似文献
4.
对于参教平面内由n个三角形构成的区域,按逆时针方向依次从1到n编号。第一步,在第1个三角形域上按插值条件确定一张曲面,利用微分几何知识,按逆时针方向利用插值条件和上一张曲面在第2个三角形域上确定一张曲面。依次下去,可得到第n个三角形域上的曲面。第二步,在第n个三角形域上按插值条件确定一张曲面,然后按顺时针方向及第一步的构造方法依次在每个三角形区域上再构造一张曲面。这样每个区域上对应着两张曲面。对于每个区域上的两张曲面进行适当叠加得到一张新曲面,这些新曲面沿其公共边界可实现切平面连续拼接。找到一个构造方法,此方法所用的曲面次数最低而且形状调节因子多,因而易于实现构造实际曲面。 相似文献
5.
6.
利用奇异混合函数将双三次B样条曲面与虚拟曲面片作混合,构造一类可插值给定数据点的插值曲面,该类曲面在边界处可达到C~2连续,参数α可对曲面片整体形状进行调控。进一步,构造了可局部调控形状的带形状参数的插值曲面。 相似文献
7.
研究了二次曲面即低次隐式曲面在各种网格条件下的情况，并得出结论：二次曲面作为C″连续的网格插值曲面一般是不可能的，并指出隐式曲面不适合作为网格插值曲面、而高阶的NURBS曲面可作为网格插值曲面。 相似文献
8.
根据拼接中的主曲面和辅助曲面方程,利用同伦映射方法构造出含有单位区间变元的代数方程,应用Sylvester结式方法消去变元得到拼接曲面表达式.然后,假设该曲面表达式能够进行因式分解,分析G0和G1次光滑拼接中拼接曲面的次数最低时辅助曲面S（hi）应满足的条件.最后,运用Grobner基理论判断分解因式后各因式是否在主曲面和辅助曲面生成的理想中,从而得出符合条件的低次拼接曲面. 相似文献
9.
本文通过讨论算子半群母元预解式的增长阶性质，得到了在t〉t0（t0≥0）时按一致范数连续的C-半群的两个特征定理，刻画了最终一致连续C-半群的稳定性。 相似文献
10.
研究目的:研究人工骨骼等细长工件的无弯折加工方法。创新要点:1.提出了一种基于曲面变形的渐进式加工方法,该方法保证加工余量在全曲面均匀分布,防止工件弯折;2.利用能量最小化实现T样条曲面的渐进变形;3.将该方法应用于以T样条曲面表示的人工指骨加工中。研究方法:1.算法总体分为生成多层变形曲面和层内刀具路径规划两部分(见图5);2.对T样条曲面采用基于能量最小化的变形方法,以加工切深作为变形约束条件,生成多层变形曲面作为每刀的加工目标形状(见图10);3.每层变形曲面内按限残高标准生成刀具路径(见图12)。重要结论:采用该加工方法可以提高细长形工件的加工质量,保证加工后形状误差不超限。 相似文献
11.
MO Guo-liang ZHAO Ya-nan 《浙江大学学报(A卷英文版)》2006,7(12):2043-2049
INTRODUCTION B-spline curves and surfaces have been widely used in Computer Graphics (CG) and Computer Aided Design (CAD) (Hoschek and Lasser, 1993; Piegl and Tiller, 1997). Many practical algorithms, such as those for position and derivatives evaluation, knot insertion, knot deletion and degree elevation, are usually implemented in a CAD system that uses B-spline as a shape design tool. In curve and surface design, a given B-spline curve or surface usually needs to be extended in … 相似文献
12.
双三次有理Bezier曲面G1光滑拼接算法 总被引：1，自引：0，他引：1
依据有理Bezier曲面理论,研究了有理Bezier曲面的拼接问题,给出了具有公共边界曲线的两张双三次有理Bezier曲面G1光滑拼接条件. 相似文献
13.
This paper presents a quadratic programming method for optimal multi-degree reduction of Bézier curves with G1-continuity. The L2 and l2 measures of distances between the two curves are used as the objective functions. The two additional parameters, available from the coincidence of the oriented tangents, are constrained to be positive so as to satisfy the solvability condition. Finally, degree reduction is changed to solve a quadratic problem of two parameters with linear constraints. Applica 相似文献
14.
在校大学生入党动机问卷调查报告——基于194份问卷的分析与研究 总被引：1，自引：0，他引：1
党首兴 《商丘职业技术学院学报》2011,10(6):5-6,33
端正大学生的入党动机,对于保证党员队伍的纯洁性、先进性、保证党建和反腐倡廉工作的顺利进行,都具有重要的影响作用,也是衡量一名大学生能否成为真正的共产党员的思想基础。调企并分析大学生入党动机正确与否,不仅关系到大学生党员队伍的质量,也关系到党员先进性的发挥,更关系到党的未来。因此,对当代大学生人党动机的调查研究及其多元取向的原因分析,对于引导大学生树立正确的入党动机,确保党的纯洁和党的事业后继有人都具有十分重要的意义。 相似文献
15.
LU Li-zheng WANG Guo-zhao 《浙江大学学报(A卷英文版)》2007,8(10):1657-1662
This paper presents a quadratic programming method for optimal multi-degree reduction of Bézier curves with G1-continuity. The L2 and l2 measures of distances between the two curves are used as the objective functions. The two additional parameters, available from the coincidence of the oriented tangents, are constrained to be positive so as to satisfy the solvability condition. Finally, degree reduction is changed to solve a quadratic problem of two parameters with linear constraints. Applica 相似文献
16.
Curve and surface blending is an important operation in CAD systems, in which a non-uniform rational B-spline （NURBS） has been used as the de facto standard. In local comer blending, two curves intersecting at that comer are first made disjoint, and then the third blending curve is added-in to smoothly join the two curves with G^1- or G^2-continuity. In this paper we present a study to solve the joint problem based on curve extension. The following nice properties of this extension algorithm are exploited in depth： （1） The parameterization of the original shapes does not change; （2） No additional fragments are created. Various examples are presented to demonstrate that our solution is simple and efficient. 相似文献
17.
This paper presents a novel approach to consider optimal multi-degree reduction of Bézier curve with G1-continuity. By minimizing the distances between corresponding control points of the two curves through degree raising, optimal approximation is achieved. In contrast to traditional methods, which typically consider the components of the curve separately, we use geometric information on the curve to generate the degree reduction. So positions and tangents are preserved at the two endpoints. For satisfying the solvability condition, we propose another improved algorithm based on regularization terms. Finally, numerical examples demonstrate the effectiveness of our algorithms. 相似文献
18.
沈阳大学女生排球项目学习动机的调查分析 总被引：4，自引：0，他引：4
陈焕坤 《鞍山师范学院学报》2005,7(2):76-78
通过对沈阳大学女学生学习排球运动项目学习动机的调查分析，指出要注重提高学生对排球运动的理论认识，并提出了培养学生良好的学习动机的方法． 相似文献
19.
We present a novel approach for dealing with optimal approximate merging of two adjacent Bezier curves with G2-continuity. Instead of moving the control points, we minimize the distance between the original curves and the merged curve by taking advantage of matrix representation of Bezier curve's discrete structure, where the approximation error is measured by L2-norm. We use geometric information about the curves to generate the merged curve, and the approximation error is smaller. We can obtain control points of the merged curve regardless of the degrees of the two original curves. We also discuss the merged curve with point constraints. Numerical examples are provided to demonstrate the effectiveness of our algorithms. 相似文献