在R编程中修正波动率曲面图的插值

This script below pulls yahoo data via a function in quantmod, then massages the data around to forumalate a 3D graph with RGL library, attached is a ggplot to show the data i'm trying to create a surface with in separate line geoms . the issue is that the 3D graph looks very ugly and cut up because of the limited quantities of points on the front month expirations.. can anyone tell me whats going on here , what i can do to fix this.. do i need to smooth each expiration's line then interpolate.... ?? This script below pulls yahoo data via a functi