Focusing on the fact that the engineering complex curves or surfaces can not be described by using a single curve or surface
the continuity conditions of cubic quasi-Bézier(cubic Q-Bézier)curves and surfaces with shape parameters are investigated. Following the analysis of basis functions and terminal properties
the necessary and sufficient conditions of G
1
G
2
continuity and C
1
C
2
continuity between two adjacent cubic Q-Bézier curves are proposed. And then
the geometric model of the cubic Q-Bézier surfaces is constructed and the condition of G
1
continuity between two adjacent cubic Q-Bézier surfaces in u and v directions is derived and simplified by choosing the control parameters properly. The modeling examples illustrate that the continuit
y condition of the cubic Q-Bézier curves and surfaces can be widely applied to the complex curves and surfaces modeling system.
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references
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