The geometric characteristics and the construction for cubic indirect Pythagorean-hodograph (indirect-PH) curves are presented in this study. By introducing an auxiliary control point and a parameter respectively, two geometric characteristics in terms of quantities related to Bézier control polygon of the curve are given. Furthermore, based on the derived conditions we provide a new geometric modeling approach for the construction of cubic indirect-PH curves in detail. And at the end of this paper several numerical examples are presented to show the feasibility and validity of our algorithm.
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