[R] mgcv : 3-way interaction and 3D-plots ?

[varin sacha]

Dear R-experts,

I have fitted a model with 2-way and 3-way interactions. 
I would like, for the 3-way interaction (year,age,by=education), to obtain 3D-plots. How could I do that ?

Many thanks for your response.

Here is the reproducible example:

############# 
install.packages("ISLR")

library(ISLR)

install.packages("mgcv")

library(mgcv)

mod1<-gam(wage ~education+s(age,bs="ps")+year+te(age,year,bs="ps")+s(year,bs="ps",by=education,m=1)+te(year,age,by=education,bs=rep("ps",2)),data=Wage)

plot(mod1)
#############