Hi,
The angle you want to calculate is : (360° - R) - A
where R is the Reference angle in degrees and A the new angle in degrees.
But as CAB said vla-Rotate needs angles in radians (as getangle, getorient, angle returned values)
(setq ent (car (entsel))
pt (getpoint "\nBasePoint :")
r (getangle "\nReference angle: ")
a (getangle pt "\nNew angle: ")
)
(vla-rotate
(vlax-ename->vla-object ent)
(vlax-3d-point pt)
(+ (- (* 2 pi) r) a)
)