tangent vector meaning in English

切失量
切矢量
正切向量

By adjusting the given tangent vector , the parametric rational arc spline also has convexity preserving property and monotonicity preserving property
在实际操作中，通过调整一侧端点的切向量，可使上述圆弧样条曲线保凸，保单调。
The approach to exactly calculate geometric parameters of subdivision surface , such as limiting point , tangent vector and normal vector , are illustrated . ( 2 ) the number of geometric elements ( vertex , edge , facet ) within control mesh grows exponentially as the increase of subdivision levels in general subdivision schemes
( 2 )在正常的曲面细分过程中，控制网格上几何元素(顶点、边、面)的数量是按照几何级数增加的，会产生庞大的冗余数据。