vlax-curve-getFirstDeriv

(vlax-curve-getFirstDeriv ename parameter)

The vlax-curve-getFirstDeriv function computes the first derivative at a specified point on the specified entity.

Arguments

ename specifies the entity to be evaluated.

parameter specifies the value of the parameter specifying a point on the entity.

Return Value

The function returns the WCS coordinates of the first derivative vector as a list of three floating-point numbers. If the function fails, it returns nil.