In plotting the Bezier 3 next curved line ideal t decisive manner

摘要

PURPOSE:To obtain a proper value adapted to the shape of a curve by using a maximum value of the change rate related to a parameter (t) from a coaxial line to P(t) to determine a step interval DELTAt of (t) required for expression from Berge cubic curve to P(t). CONSTITUTION:A maximum change rate Dx in the (x) direction and a maximum change rate Dy in the (y) direction in the range of 0=t=1 from the Berge cubic curve to P(t) expressed with a formula are obtained. Based on Dx, Dy, and desired minimum plot intervals DELTAPx and DELTAPy in (x) and (y) directions, a step interval DELTAtx in the (x) direction and a step interval DELTAty in the (y) direction of (t) are obtained in accordance with DELTAtx=Px/Dx and DELTAty=Py/Dy. Smaller one of DELTAtx and DELTAty is defined as the step interval DELTAt of (t). When minimum plot intervals DELTAPx and DELTAPy may have the same value DELTAP, Dx and Dy are compared with each other and larger one of them is defined as a maximum change rate, and the step interval DELTAt of (t) is obtained in accordance with DELTAt=DELTAP/D.